855

855 = 3² x 56 x 19.

855 is the sum of all the digits of all two-digit numbers.

855 is a number that cannot be written as a sum of three squares.

855 is a decagonal number. It is also a centered cube number.

855 is the smallest number that is the sum of five consecutive squares and two consecutive cubes: 855 = 11² + 12² + 13² + 14² + 15² = 7³ + 8³.

855 Newcombia is a asteroid discovered in 1916.

Source: Number Gossip