And in general, if you have a prime factorization:n = 2^x 3^a 5^b
-the number of positive divisors of n will be (x+1)*(a+1)*(b+1)
-the number of odd positive divisors of n will be (a+1)*(b+1)
-the number of even positive divisors of n will be x*(a+1)*(b+1)
This will be true no matter what primes you have in your factorization - the odd primes don't need to be 3 and 5 - and regardless of how many primes you have in the prime factorization (I used two odd primes just for illustration).
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