637

637 = 7 x 7 x 13.

637 is a decagonal number.

637 is 777 in base 9. It is 212121 in base 3 and 1600 in base 7.

637 has a representation as a sum of two squares: 637 = 14² + 21².

637³ = 258,474,853 = (258 - 474 + 853)³.

Source: What's Special About This Number?