Thread: Sum of positive integer divisor

Let *(x) be the function that calculates the sum of positive integer divisors of x.

i.e *(6) = 1+2+3+6 = 12

How do I go about finding all x such that *(x) = 12?

Thanks

You definitely know that , so how about using brute force?

I need to find a pattern or formula of some sort. The next problem is to find x such that *(x) = 56. Brute force isn't exactly ideal here...