450

450 = 2 x 3² x 5².

450 has two representations as a sum of two squares: 450 = 3² + 21² = 15² + 15².

450 is 3300 in base 5, 1212 in base 7, 550 in base 9, 242 in base 14, and 200 in base 15.

450 is the sum of two consecutive primes: 450 = 223 + 227.

450 and 450² = 202,500 have the same digit sum: 4 + 5 + 0 = 2 + 0 + 2 + 5 + 0 + 0 = 9.

450 is a perfect score in Canadian five-pin bowling.

Source: On-Line Encyclopedia of Integer Sequences