28

This number is a composite.

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The second perfect number. Leonhard Euler (1707-1783) proved that all even perfect numbers are of the form 2^n-1(2ⁿ - 1), where 2ⁿ - 1 is a Mersenne prime M_n.

Submitted: 2000-06-16 15:24:11; Last Modified: 2021-08-07 01:20:34.