48

48 = 2⁴ x 3.

48 is the smallest number to have ten different factors: 1, 2, 3, 4, 6, 8, 12, 16, 24, and 48.

48 = 3 + 5 + 7 + 9 + 11 + 13.

48 has a unique representation as a sum of three squares: 48 = 4² + 4² + 4².

48 is the smallest number with five representations as a sum of two primes: 48 = 5 + 43 = 7 + 41 = 11 + 37 = 17 + 31 = 19 + 29.

48 is 66 in base 7.

The 48 Preludes and Fugues by Johann Sebastian Bach (1685-1750) make use of all the major and minor musical keys.

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