Perfect number

[Utkrisht123]

Perfect numbers are number whose sum of factors are twice the number itself.

Example

1. 6 factors of 6 are 1,2,3 and 6 sum=12 i.e 2 * 6

2. 28 factors 1,2,4,7,14,28 sum=56 i.e 2 * 28

can you tell any other perfect no?

[Prime]

I am only aware of this general rule.

P = 2

^p-1(2^p - 1), where M = 2^p - 1 is a Mersenne prime.
Example:
2*(2² - 1) = 6
2²*(2³ - 1) = 28
2⁴*(2⁵ - 1) = 496
2⁶*(2⁷ - 1) = 8128
etc.

That is not to say there aren't any other possibilities for finding perfect numbers.

[TimeSpaceLightForce]

1 factors 1, 1 sum =2 i.e. 2*1

Edited March 23, 2013 by TimeSpaceLightForce

[Utkrisht123]

1 factors 1, 1 sum =2 i.e. 2*1

1 has only 1 as a factor so sum is 1

[wolfgang]

Didn`t find one yet

Edited March 23, 2013 by wolfgang

[TimeSpaceLightForce]

Perfect numbers are number whose sum of factors are twice the number itself.

Example

1. 6 factors of 6 are 1,2,3 and 6 sum=12 i.e 2 * 6

2. 28 factors 1,2,4,7,14,28 sum=56 i.e 2 * 28

can you tell any other perfect no?

I would rather say they are half perfect because their factors sum is twice of them. 1 is perfect.

[marksmanjay]

COMBINATION: 4927

[Prime]

Perfect numbers are number whose sum of factors are twice the number itself.

Example

1. 6 factors of 6 are 1,2,3 and 6 sum=12 i.e 2 * 6

2. 28 factors 1,2,4,7,14,28 sum=56 i.e 2 * 28

can you tell any other perfect no?

I would rather say they are half perfect because their factors sum is twice of them. 1 is perfect.

In old (Euclid) times, they did not count the number as its own divisor, but they did count 1. Thus, Perfect Number used to be equal to the sum of its divisors (Aliquot Parts.)

(Don't quote me on that.)