Question

Prove the following:
If k is a positive integer and (2^k)-1 is prime, then (2^(k-1))*((2^k)-1) is perfect.

A number n is perfect if the sum of all it's positive divisors (including 1 and itself) is 2n. Prove the following:
If k is a positive integer and (2^k)-1 is prime, then (2^(k-1))*((2^k)-1) is perfect.

A number n is perfect if the sum of all it's positive divisors (including 1 and itself) is 2n. @Mathematics

Answer 1

Try looking here http://primes.utm.edu/notes/proofs/EvenPerfect.html

Answer 2

yeah I found that too, I just don't know what sigma is

Answer 3

It's just the sum of the positive divisors of n http://primes.utm.edu/glossary/page.php?sort=SigmaFunction

Answer 4

oh I see, I will take another look at that proof then