Write the set of prime factors of 3234.

Factors of 3234 = 1, 2, 3, 6, 7, 11, 14, 21, 22, 33, 42, 49, 66, 77, 98, 147, 154, 231, 294, 343, 462, 686, 1029, 1372, 2058, 3234

Prime factors of 72 = 2, 3, 7, 11

{ 2, 3, 7, 11}