65,536

← 65535 65536 65537 →
Cardinalsixty-five thousand five hundred thirty-six
Ordinal65536th
(sixty-five thousand five hundred thirty-sixth)
Factorization216
Divisors1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536
Greek numeral͵εφλϚ´
Roman numeralLXVDXXXVI, lxvdxxxvi
Binary100000000000000002
Ternary100222200213
Senary12232246
Octal2000008
Duodecimal31B1412
Hexadecimal1000016

65536 is the natural number following 65535 and preceding 65537.

65536 is a power of two: (2 to the 16th power).

65536 is the smallest number with exactly 17 divisors (but there are smaller numbers with more than 17 divisors; e.g., 180 has 18 divisors) (sequence A005179 in the OEIS).

The preceding power of 2 from 65,536 is 32,768

The following power of 2 from 65,536 is 131,072

256×256 grid with 65536 squares

In mathematics

65536 is , so in tetration notation 65536 is 4 2.

When expressed using Knuth's up-arrow notation, 65536 is , which is equal to , which is equivalent to or .

As is also equal to 4, or , can thus be written as , or , or as the pentation (hyperoperation notation).

65536 is a superperfect number – a number such that σ(σ(n)) = 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 to 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.

The sum of the unitary divisors of 65536 is prime (1 + 65536 = 65537, which is prime).

65536 is an untouchable number.

In computing

65,536 (216) is the number of different values representable in a number of 16 binary digits (or bits), also known as an unsigned short integer in many computer programming systems.

This number is a limit in many common hardware and software implementations, some examples of which are:

References

  1. ↑ Weisstein, Eric W. "Superperfect Number". MathWorld.
  2. ↑ Wells, David (1997). The Penguin Dictionary of Curious and Interesting Numbers (revised ed.). Penguin. ISBN 0-14-026149-4.
  3. ↑ 65536 at Prime Pages
  4. ↑ "General Purpose Operating System Support for Multiple Page Sizes" (PDF). static.usenix.org. Retrieved 2012-11-02.
  5. ↑ Microsoft Help Q120596
  6. ↑ "Enable multidex for apps with over 64K methods".
  7. ↑ "WhatsApp Business: Character Limits and Other Restrictions". engageSPARK. 2025-04-02. Retrieved 2025-12-03.