# Sum of positive integer divisor

• October 21st 2011, 11:16 PM
jzellt
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
• October 22nd 2011, 07:24 AM
roninpro
Re: Sum of positive integer divisor
You definitely know that $x< 12$, so how about using brute force?
• October 22nd 2011, 02:05 PM
jzellt
Re: Sum of positive integer divisor
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...