496 (number)

← 495 496 497 →
List of numbers — Integers ← 0 100 200 300 400 500 600 700 800 900 →
Cardinal	four hundred ninety-six
Ordinal	496th (four hundred and ninety-sixth)
Factorization	2^4× 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 ninety-six is the natural number following four hundred ninety-five and preceding four hundred ninety-seven.

In mathematics

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.^[1] Being the 31st triangular number, 496 is the smallest counterexample to the hypothesis that one more than an even 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

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

• AD 496

References

1. "Centered 9-gonal numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-16.