427

427 = 7 x 61.

427 has a unique representation as a sum of three squares: 427 = 9² + 11² + 15².

427 is a value of n for which n! + 1 is a prime (A002981).

427 is 110101011 in base 2 (binary) (A006995) and 1551 in base 6.

427 is the solution to the postage stamp problem for 4 denominations and 10 stamps (A001209).

Source: What's Special About This Number?