88

88 = 2³ x 11.

88 has a unique representation as a sum of three squares: 88 = 4² + 6² + 6².

88 = 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13.

88 is the sixth number that stays the same when written upside down.

88 is the smallest number such that its square has all its digits twice: 88² = 7744.

A modern piano has 88 keys, 52 white and 36 black, spanning more than seven octaves.

88 is the number of constellations in the sky, as defined by the International Astronomical Union.

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