Compute the sum of all positive integers k for which the number k*1984 has exactly 21 positive divisors.
1984 = 2^6 * 31
Just multiply 1984 x 31 =(1, 2, 4, 8, 16, 31, 32, 62, 64, 124, 248, 496, 961, 992, 1922, 1984, 3844, 7688, 15376, 30752, 61504) >>Total = 21 divisors
31 =3 + 1 =4
Thankyou so much :)
+134 
