496 (number)

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495 496 497
Cardinal four hundred and ninety-six
Ordinal 496th
(four hundred and ninety-sixth)
Factorization 24· 31
Roman numeral CDXCVI
Binary 1111100002
Ternary 2001013
Quaternary 133004
Quinary 34415
Senary 21446
Octal 7608
Duodecimal 35412
Hexadecimal 1F016
Vigesimal 14G20
Base 36 DS36

Four hundred [and] ninety-six is the natural number following four hundred [and] ninety-five and preceding four hundred [and] ninety-seven.

In mathematics[edit]

496 is most notable for being a perfect number, and one of the earliest numbers to be recognized as such. As a perfect number, it is tied to the Mersenne prime 31, 25 - 1, with 24 ( 25 - 1 ) yielding 496. Also related to its being a perfect number, 496 is a harmonic divisor number, since the number of proper divisors of 496 divided by the sum of the reciprocals of its divisors, 1, 2, 4, 8, 16, 31, 62, 124, 248 and 496, (the harmonic mean), yields an integer, 5 in this case.

A triangular number and a hexagonal number, 496 is also a centered nonagonal number and a centered 11-gonal number. Being the 31st triangular number, 496 is the smallest counterexample to the hypothesis that one more than an even indexed triangular number is a prime number. It is the largest happy number less than 500.

There is no solution to the equation φ(x) = 496, making 496 a nontotient.

E8 has real dimension 496.

In physics[edit]

The number 496 is a very important number in superstring theory. In 1984, Michael Green and John H. Schwarz realized that one of the necessary conditions for a superstring theory to make sense is that the dimension of the gauge group of type I string theory must be 496. The group is therefore SO(32). Their discovery started the first superstring revolution. It was realized in 1985 that the heterotic string can admit another possible gauge group, namely E8 x E8.

See also[edit]