"A perfect number is a natural number which is equal to the sum of its divisors, also including the number one (but excluding the number itself)" and Euclid with an algorithm, (2^n -1)*2^(n-1 ) states that even perfect numbers are the result of the multiplication between two powers that both have the number 2 as a base and the indices of the powers differ by 1, i.e.: a power is 2^n -1 which is a prime number with the other power, 2^(n -1) which is an even number. The algorithm for even perfect numbers can be extended to odd perfect numbers which are the result of the multiplication between two powers that both have the same odd number as a base and the indices of the powers differ by 1, i.e.: a power is an odd number ^n -2 which is a prime number with the other power, odd number^(n -1) which is an odd number. Perfect even or odd numbers are the result of multiplying the result between two powers one of which is a prime number (obtained from a power). The difference between even and dispar perfect numbers is: a) for even perfect numbers the prime number is the result of a power of two minus 1; b) for odd perfect numbers the prime number is the result of a power of one of the infinite odd numbers minus 2.