A number of the form 2(pā1)(2pā1) is an even perfect number if 'p' and 2(pā1) are prime numbers.
Euclid proved that 2p−1(2p − 1) is an even perfect number whenever 2p − 1 is prime. For example, the first four perfect numbers generated by the formula 2p−1(2p − 1), with p a prime number are as follows:
For p = 2: 21(22 − 1) = 2 x 3 = 6