64

64 = 2⁶.

64 is the first number after 1 to be both a square and a cube: 64 = 8² = 4³.

64 is the number of integer partitions of 20 into distinct parts.

64 is 121 in base 7 and 44 in base 15. It is 1000000 in base 2, 1000 in base 4, 100 in base 8, 40 in base 16, and 20 in base 32.

The Commodore 64 was an 8-bit home computer introduced in 1982.

Source: Phillips, R. 1994. Number Facts, Figures and Fiction. Cambridge University Press.