Prime factorization of 500 = 2 x 2 x 5 x 5 x 5
Including 1, the number of factors with the combination of 2’s = 3
These 3 factors when multiplied with each of the combinations of 5 gives another 3 x 3 = 9 factors
Hence the total number of factors for 500 = 3 + 9 = 12