An integer n is called perfect if it equals the sum of all its divisors d 1<d<n
Let a be a positive integer. Prove that if 2^a -1 is prime, the n= 2^(a-1) (2^a - 1) is perfect.
I did not know what meant until I read up on the Mersenne prime and Euclid's proof.
My book has devoted only one chapter on number theory, and I was expected to this proof without much instruction. I am glad you showed the proof.
I am an engineering student. I learn pure math on my own. Could you recommend me a book on number theory that's easy for my independent study.