65,536


65536 is the natural number following 65535 and preceding 65537.
65536 is a power of two: .
65536 is the smallest number with exactly 17 divisors.

In mathematics

65536 is, so in tetration notation 65536 is 42.
When expressed using Knuth's up-arrow notation, 65536 is
which is equal to
which is equivalent to
or
65536 is a superperfect number – a number such that σ = 2n.
A 16-bit number can distinguish 65536 different possibilities. For example, unsigned binary notation exhausts all possible 16-bit codes in uniquely identifying the numbers 0..65535. In this scheme, 65536 is the least natural number that can not be represented with 16 bits. Conversely, it is the "first" or smallest positive integer that requires 17 bits.
65536 is the only power of 2 less than 231000 that does not contain the digits 1, 2, 4 or 8 in its decimal representation.
65536 is the largest known number such that the sum of its unitary divisors is prime.
65536 is an untouchable number.

In computing

65536 is the number of different values representable in a number of 16 binary digits, also known as an unsigned short integer in many computer programming systems. This can place a limitation on many common hardware and software implementations, some examples of which are: