Sixty-four

64 is the natural number following 63 and preceding 65.

List of numbers — Integers << 60 61 62 63 64 65 66 67 68 69 >>
Cardinal	sixty-four
Ordinal	64th (sixty-fourth)
Numeral system
Factorization	<math>2^6\,\!<math>
Divisors	2, 4, 8, 16, 32
Roman numeral	LXIV
Binary	1000000
Hexadecimal	40

Sixty-four is the square of 8 and the cube of 4. It is the lowest positive power of two that's surrounded by neither a Mersenne prime nor a Fermat prime. It is also a dodecagonal number and a centered triangular number. 64 is a self number.

Sixty-four is also:

• The atomic number of gadolinium, a lanthanide.
• In some computer programming languages, the size in bits of certain data types.
• In chess, the total number of black and white squares on the board.
• The code for international direct dial calls to New Zealand.
• The designation of US Interstate 64, a freeway from Missouri to Virginia.
• The subject of the Beatles song When I'm Sixty-Four
• The registry of the U.S. Navy's aircraft carrier USS Constellation (CV-64)
• The number of Braille characters in the old 6-dot system.
• The year AD 64, 64 BC, or 1964.
• In video games, the Nintendo 64 video game console and the Commodore 64. Since 1996, the number 64 is usually the abbreviation or slang for Nintendo 64.