Hexakosioihexekontahexaphobia

Hexakosioihexekontahexaphobia (pronounced hex-ax-oh-gee-oh-e-eye-hex-en-gen-too-hex-a-pho-be-ah)

Fear of the number 666.

The number 666 is best known from the New Testament’s Book of Revelation (13:15–18) and is a symbol both of the Antichrist and the Devil and is applied to the second of two beasts mentioned in the Book of Revelation.  The construct was the Ancient Greek ἑξακόσιοι (hexakósioi) (six hundred) + ἑξήκοντα (hexḗkonta) (sixty) + ἕξ (héx) (six) +‎ -phobia.  The suffix -phobia (fear of a specific thing; hate, dislike, or repression of a specific thing) was from the New Latin, from the Classical Latin, from the Ancient Greek -φοβία (-phobía) and was used to form nouns meaning fear of a specific thing (the idea of a hatred came later).  For certain historians and biblical scholars for whom 616 is as suspect as 666 there's the companion phobia: Hexakosioihekkaidekaphobia.   The related forms are hexakosioihexekontahexaphobe & hexakosioihexekontahexaphobic.  For help when practicing pronunciation, go to:

https://www.howtopronounce.com/hexakosioihexekontahexaphobia/

The number of the beast

The origin is murky and there are other biblical references but not always as 666; 666 is the number of talents of gold Solomon collected each year and is the number of Adonikam's descendants who return to Jerusalem and Judah from the Babylonian exile and scholars suggest there are latent references in transliteration.   Nebuchadnezzar, the sixth-century BC king of Babylon, appears both as Nebuchadrezzar and Nebuchadrezzur and the number of each name can be calculated because in the Hebrew, letters double as numbers.  Nebuchadrezzar is 663, and Nebuchadrezzur, 669; midway between the two lies 666 and it was Nebuchadrezzar, who came (bidden by God) to crush God's people so may thus prefigure the end of times beast, the antagonistic creature which appears briefly about two-thirds into Revelation’s apocalyptic vision. Some manuscripts of the original Greek use the symbols χξϛ or χξϝ while other manuscripts spell out the number in words.  Using gematria (the method of calculating numbers from names), Nero Caesar transliterated from Greek into Hebrew produces the number 666 whereas the Latin spelling renders 616.  Thus, 666 may be a coded reference to Nero, although that notion does depend on the accepted Hebrew spelling of Caesar, a thing about which there’s some doubt. 

For two millennia there’s never been ecclesiastical or scholarly consensus about 666.  Although the second century Greek cleric Irenaeus affirmed 666, theologians then and since have expressed doubts because of the appearance of 616 in the Codex Ephraemi Rescriptus, one of the four great uncial codices, as well as in the Latin version of Tyconius and an ancient Armenian version.  Irenaeus knew about 616 but choose, for whatever reason, to correct the Vetus Latina, the existing Latin version of the New Testament.  The oldest known manuscript of Revelation, from Papyrus 115 in the Oxyrhynchus series, uses 616, as does the later Codex Ephraemi Rescriptus, even having 616 written in full: ἑξακόσιοι δέκα ἕξ, hexakosioi deka hex (six hundred and sixteen).  These documents are cited by some scholars who suggest 616 was the original, 666 substituted by analogy with 888, the Greek number for Jesus. 

More fun, and just as speculative, is the idea the writers of the time just liked numbers, 666 being more interesting than 616 because:

(1) 666 is a triangular number, the sum of the first 36 natural numbers (ie 1+2+3+4+5+6+...+36=666).  That of course makes 666 the sum total of the numbers on a roulette wheel.  Zero, so often of such significance, here has no effect. 

(2) 666 is the sum of squares of the first seven prime numbers.

(3) In Roman numerals 666 is DCLXVI which has exactly one occurrence of all symbols whose value is less than 1000 in decreasing order (D=500, C=100, L=50, X=10, V=5, I=1).

(4) In base 10, 666 is a repdigit (and therefore a palindromic number) and a Smith number.  A prime reciprocal magic square based on 1/149 in base 10 has a magic total of 666.

The Number of the Beast is 666 (circa 1805), pen and watercolor, by William Blake (1757-1827).

Thanks to popular culture, even beyond Christendom, the number 666 and its relationship with the Devil and the Antichrist is well known and it clearly affects a few.  When in 1989 Ronald Reagan (1911-2004 US president 1981-1989) retired to leafy rich Bel-Air in Los Angeles (a locality which maintained its prestige despite the indignity of the Chevrolet Bel Air between 1950-1972 being reduced from a premium to a basic designation), although happing with the house at 666 St Cloud Road, they soon had the address changed to 668.  Whether this was on advice from Nancy Reagan’s (1921-2016) clairvoyant isn’t recorded but some organs of the US state also chose not to take chances.  US Route 666 (dating from 1926), upon statistical analysis, proved unusually dangerous and after this became public knowledge it picked up the nickname the Devil’s Highway.  In 2003 it was renamed US Highway 491 and the accident rate has lowered although its thought this is due to improvements to the road and a reduction in the number of people stopping to steal road signs, Route 666 a popular destination for stoners to pose for photographs, a thing even in the pre-selfie era.  In more secular Finland, there was apparently little concern, Finair flight AY666 plying the CPH-HEL (Copenhagen-Helsinki) route between 2006-2017, AY666 retired and replaced by AY954 as part of a general restructuring.  AY666’s last flight was on a Friday the 13^th (for the 21^st time) and it landed safely, eight minutes ahead of schedule.

Names for many phobias have been coined and while some (relating to injections, spiders, heights etc) are of clinical significance in mental health, many have been created just for linguistic fun.  A surprising number relate to numbers, many of which reference popular culture (TV, video games etc) and a site exists which provides a précis of many.  The overarching condition is arithmophobia (also known as numerophobia), which is a fear of numbers or mathematics but among the specifics there are:

Oudenophobia (0)
Henophobia (1)
Dyophobia (2)
Triskaphobia (3)
Tetraphobia (4)
Pentaphobia (5)
Hexaphobia (6)
Heptaphobia (7)
Octophobia (8)
Enneaphobia (9)
Decaphobia (10)
Hendecaphobia (11)
Dodecaphobia (12)
Triskaidekaphobia (13)
Dekapentophobia (15)
Hexadecaphobia (16)
Heptadecaphobia (17)
Octodecaphobia (18)
Enneadecaphobia (19)
Eikositriophobia (23)
Eikosihexaphobia (26)
eikosiheptaphobia (27)
Triakontenneaphobia (39)
Tessarakontadyophobia (42)
Tessarakontaheptaphobia (47)
Pentekontoctophobia (58)
Hexekontadyophobia (62)
Hexekontenneaphobia (69)
Hebdomekontahenophobia (71)
Ogdokontaheptaphobia (87)
Enenekontenneaphobia (99)
Hekatophobia (100)
Hekatohendecaphobia (111)
Hekatenenekontahenophobia (191)
Diakosioihekkaidekaphobia (216)
Diakosioipentekontaphobia (250)
Triakosioitriakontatriophobia (333)
Tetrakosioeikosiphobia (420)
Pentakosioipentekontahenophobia (551)
Hexakosioihekkaidekaphobia (616)
Hexakosioihexekontahexaphobia (666)
Heftakosioitessarakontaheptaphobia (747)
Enniakosioihendecaphobia (911)
Enniakosioenenekontenneaphobia (999)
Quattuormiliasescentoruphobia (4600)
Tessarakontadyochilahexekontenneaphobia (42069)
Compustitusnumerophobia (composite numbers)
Meganumerophobia (large numbers)
Imparnumerophobia (odd numbers)
Omalonumerophobia (even numbers)
Piphobia (pi)
Phiphobia (the golden ratio)
Primonumerophobia (prime numbers)
Paranumerophobia (irrational numbers)
Neganumerophobia (negative numbers)
Decadisophobia (decimals)

Just because a "phobia" appears in a list doesn't mean it "exists" in a clinical sence; there are doubtless many listed "phobias" which have never afflicted a single individual, their coining simply because someone decided to prove it was possible and an AI bot presumably could create many more.  Indeed, because of the infinite number of numbers, the number of potential "number phobias" is similarly infinite.  Some though may be real henophobia (fear of 1) is said to compels sufferer to avoid being associated with “doing something once”, being the “first in the group” etc) while eikosiheptaphobia (fear of 27) is a pop-culture thing which arose in the early 1970s when a number of rock stars died messy, drug-related deaths at 27).  Presentations of patients with tessarakontadyophobia (fear of 42) may have spiked in patients after the publication of Douglas Adams’ (1952–2001) Hitchhiker's Guide to the Galaxy (1979-1992) but enenekontenneaphobia (fear of 99) is thought unrelated to the Get Smart TV series of the 1960s.  Tetrakosioeikosiphobia (fear of 420) is a syndrome restricted presumably to weed-smokers in the US although it could also be a thing among those with a morbid dread of 4 February or 20 April (depending on where one lives) and although heftakosioitessarakontaheptaphobia (fear of 747) may have had something to do with the Jumbo Jet, with the withdrawal from passenger service of the tough, reliable (four engines and made of metal) Boeing 747 and its replacement by twin-engined machines made increasingly of composites and packed with lithium-ion batteries, a more common fear may be “not flying on a 747”).  Closer to earth, enniakosioihendecaphobia (fear of 911), in the US may be a co-morbidity with tetrakosioeikosiphobia or suffered by those with a bad experience with a pre-modern Porsche 911 which, in inexpert hands, could behave as one would expect of a very powerful Volkswagen Beetle.  The rare condition nongentiseptuagintatrestrillionsescentiquinquagintanovemmiliacentumtredecimdeciesoctingentivigintiquattuormiliatrecentiphobia (fear of 973,659,113,824,315) was almost certainly one of those coined as a linguistic exercise.  The marvellous Wiki Fandom site and The Phobia List are among the internet’s best curated collection of phobias.

Phobias can be coined ad-hoc.  In 2008, Time magazine pondered lindsayphobia.  

The only one which debatably can’t exist is neonumerophobia (fear of new numbers) because, given the nature of infinity, there can be no “new numbers” although, subjectively, a number could be “new” to an individual so there may be a need.  Sceptical though mathematicians are likely to be, the notion of the “new number” has (in various ways) been explored in fiction including by science fiction (SF or SciFi) author & engineer Robert A Heinlein (1907–1988) in The Number of the Beast (1980), written during his “later period”.  More challenging was Flatland: A Romance of Many Dimensions by English schoolmaster & Anglican priest Edwin Abbott Abbott (1838–1926) which was published under the pseudonym “A Square”, the layer of irony in that choice revealed as the protagonist begins to explore dimensions beyond his two-dimensional world (in Victorian England).  Feminists note also Ursula K Le Guin’s (1929–2018) The Left Hand of Darkness (1969) in which was created an entirely new numerical system of “genderless" numbers”.  That would induce fear in many.

The latest edition of the American Psychiatric Association’s (APA) Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR, March 2022) made few changes to the classification anxiety disorders and phobias which had been revised in DSM-5 (2013).  Phobias are categorized as anxiety disorders, with specific phobia (fear of something that poses little or no actual danger) being the most common anxiety disorder.  A specific phobia is said to manifest when a person experiences extreme anxiety when they anticipate exposure or are exposed to a feared stimulus and there are five general categories: (1) animal type (spiders, snakes, dogs etc), (2) the natural environment (tornadoes, heights, water, fire etc), (3) injections and related procedures (needles, medical procedures), (4) situational events (flying, enclosed spaces etc ) & (5) other types (ie phobias that do not fit into the previous four categories).  The fifth category interacts with the introduction of Generalized Anxiety Disorder (GAD) which is diagnosed when an individual experiences persistent worry about everyday challenges out of proportion to the perceived threat.  GAD extends to those aware their reaction is one of excessive fear about what can be a non-existent threat and no more than worrying about worrying too much.  Superstitions related to particular numbers are common in many cultures but of themselves these do not constitute a phobia which technically is a diagnosis of reaction to the point where the affect on a patient’s life is clinically significant.  Accordingly, while noting just about anything which has been styled a phobia could induce a case of GAD, few actually satisfy the APA’s diagnostic criteria and the DSM mentions just the handful which constitute the overwhelming majority of cases.