680 = 23 x 5 x 17.
680 is the 15th tetrahedral number. It is the smallest tetrahedral number that is also the sum of two tetrahedral numbers: 680 = 560 + 120.
680 has two representations as a sum of two squares: 680 = 22 + 262 = 142 + 222.
680 is 404 in base 13.
680 can be written as the sum of distinct odd powers of two: 680 = 23 + 25 + 27 + 29.
WCBM AM 680 is a talk radio station in Baltimore.Source: Number Gossip
