A certain positive integer has exactly 20 positive divisors. ASAP

a)  We could have two primes that divide the integer 

Suppose that the number can be prime-factored into  a^m * b^n

So

(m + 1) ( n + 1)  =  20

And  m, n    could be  (in some order)   

3, 4  or

1, 9

b )   We could have three primes that divide the integer

Suppose that the integer  can be prime-factored into  a^k * b *m * c ^n

So

(k + 1) (m + 1) ( n + 1)  = 20

And k, m, n   could be  (in some order)

1, 1, 4