Hint: Say 2 numbers are factors of . If you multiply them together, by their very definition they =
So if only had 6 factors. We could just divide by 2 to get 3 pairs of . Then the answer would be Obviously this isn't the actual number of factors since there woudn't be a 3 out front. the answer will most likely be in where a = multiple of 6.
So now you just need to know how many factors 6^16 has. Can dig around for that or reply back here, and I can let you know. There is a pretty quick way to tell using prime factorization.