Perfect Number | Theorem | Examples | Every Even perfect number ends in 6 or 8 | Lecture- 19

1. Define Perfect and multi-perfect Numbers
2. If 2^k -1 is prime number then 2^k-1(2^k -1) is perfect number
3. Prove that every even perfect number ends in 6 or 8
3. Prove sum of reciprocal of all divisor of a perfect number is 2
4. If 2%(n+1) -1 = p is prime number then prove q = p(p+1)/2 is perfect number
5. Prove that a prime number can not be perfect
6. Prove product of two odd prime numbers is not perfect number