556 = 2 x 2 x 139.
556 is the total number of parts in all partitions of 13.
556 are the first three digits of 4556.
556 is the sum of four consecutive primes: 556 = 131 + 137 + 139 + 149.
556 is an untouchable number; it is never the sum of the proper divisors of any integer.
556 Phyllis is an asteroid orbiting the sun, discovered in 1905.
U-556 was a German submarine that was built for and operated during World War II.
Source: What's Special About This Number?