Since there are two distinct factors other than 1, and itself, which implies the total number of factors of N is 4. It can be done in two ways. First case: N=p3 (where p is a prime number) Second case: N=p1×p2 (Where p1,p2 are the prime numbers) From case 1 , we can see that the numbers which is a cube of prime and less than 50 are 8 , and 27 (2 numbers). (3*7),(3*11),(3*13),(5*7){(13 numbers )} Hence, the total number of numbers having two distinct factors is (13+2)=15.