pos. integer with integer sum of the reciprocals of all its natural divisors
Source: Tuymaada Junior 2004 p6
May 11, 2019
number theorySumreciprocal sumpositive integersprime
Problem Statement
We call a positive integer good if the sum of the reciprocals of all its natural divisors are integers. Prove that if
is a good number, and is a prime number, then is not good.