666 (number)

List of numbersIntegers
0 100 200 300 400 500 600 700 800 900
Six hundred and sixty-six
Greek numeral
Roman numeral
476, i.e. 04 07 06
11 06
1 In mathematics
2 The number of the Beast
3 In other fields
4 References

In mathematics
666 is the natural number following 665 and preceding 667. It is also an abundant number. It is the sum of the first 36 natural numbers (i.e. 1 + 2 + 3 + ... + 34 + 35 + 36 = 666), and thus a triangular number. Since 36 is both square and triangular, 666 is the sixth number of the form n2(n2 + 1) / 2 (sequence A037270 in OEIS) and the eighth number of the form n(n + 1)(n2 + n + 2) / 8 (doubly triangular numbers, A002817).
666 is the sum of the squares of the first seven prime numbers (i.e. 22 + 32 + 52 + 72 + 112 + 132 + 172 = 666).
The harmonic mean of the decimal digits of 666 is (trivially -- all repdigit natural numbers have this property) an integer: 3/(1/6 + 1/6 + 1/6) = 6, making 666 the 54th number with this property.
In base 10, 666 is a palindromic number, a repdigit and a Smith number. A prime reciprocal magic square based on 1/149 in base 10 has a magic total of 666.
The Roman numeral representation of the number 666 (DCLXVI) uses once each the Roman numeral symbols with values under 1,000, occurring in descending order of their respective values (D = 500, C = 100, L = 50, X = 10, V = 5, I = 1).
666 is a member of the Indices of prime Padovan sequence, 3, 4, 5, 7, 8, 14, 19, 30, 37, 84, 128, 469, 666, 1262, 1573, 2003, 2210, ... (sequence A112882 in OEIS).

The number of the Beast
Main article: Number of the Beast
In the Bible, the Book of Revelation (13:17-18) cryptically asserts 666 to be "the number of a man", associated with the beast, an antagonistic creature that appears briefly about two-thirds into the apocalyptic vision. The author challenges the reader to figure out the symbolism of this number, a challenge that has inspired mystics and would-be prophets ever since. It is assumed by many biblical scholars to refer to Emperor Nero. The number is arrived at by presenting Nero's name in Greek (Kaisar Neron) and transforming it into Hebrew whose letters also have a numeric value. The Hebrew letters would be q=60, s=100, r=200,n=50,w=6[1].
The number of people who have been proposed to be the man whose number is 666 is vast and ever growing; it usually does not demand much ingenuity to find several ways to connect one's political or religious opponent with the number 666, since there is no biblical restriction on how a connection between a man and the number may be established.
In modern popular culture, 666 has become one of the most widely recognized symbols for Satan or the Devil. Earnest references to 666 occur both among apocalypticist Christian groups and in explicitly anti-Christian subcultures such as that surrounding some heavy metal bands; more humorous allusions to the 666 symbolism (e.g., the Lemmings level featuring three 6's built upon "hellish" lava terrain) are mainstream. An appearance of the number 666 in contemporary Western art or literature is more likely than not an intentional reference to this number of the Beast symbolism. Such popular references to 666 are too numerous to list here.
It is not uncommon to see the symbolic role of the integer 666 transferred to the digit sequence 6-6-6. Some people take the satanic associations of 666 so seriously that they actively avoid things related to 666 or the digits 6-6-6. This is known as hexakosioihexekontahexaphobia.

In other fields
In the Bible, 666 is the number of gold talents that King Solomon collected in a single year (see 1 Kings 10:14 and 2 Chronicles 9:13).
In the Bible, 666 is the number of Adonikam's descendants who return to Jerusalem and Judah from the Babylonian exile (see Ezra 2:13).
The sum of all the numbers on a roulette wheel is 666.
The number 666 is a frequent visual element of Aryan Brotherhood tattoos.
666 is the port number used by the game Doom when playing against another player via TCP.
666 was the original name of the Macintosh SevenDust computer virus that was discovered in 1998.
666 was a winning lottery number in the 1980 Pennsylvania Lottery scandal, in which equipment was tampered to favour a 4 or 6 as each of the three individual random digits.