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 Unitary perfect numbers (Posted on 2013-12-16)
A unitary divisor of a number n is a number d such that d|n and gcd(d, n/d)=1. For example, 3 is a unitary divisor of 12 because gcd(3, 12/3)=gcd(3, 4)=1.

A unitary perfect number is a number that is the sum of its unitary divisors less than itself. For example, 60 is a unitary perfect number because its unitary divisors less than itself are 1, 3, 4, 5, 12, 15, and 20, and 1+3+4+5+12+15+20=60. Find all unitary perfect numbers less than 1000000.

 Submitted by Math Man Rating: 5.0000 (1 votes) Solution: (Hide) 6, 60, 90, 87360

 Subject Author Date re(4): just look up by SH Ady TZIDON 2013-12-17 10:16:06 re(3): just ...correction Charlie 2013-12-17 10:07:19 re(3): just look up by SH Charlie 2013-12-17 10:04:18 re(2): just look up by SH Ady TZIDON 2013-12-17 04:25:33 re(2): just ...correction Ady TZIDON 2013-12-17 02:58:28 re: just look up - spoiler Steve Herman 2013-12-16 19:37:23 That was quick! Math Man 2013-12-16 19:24:14 re: just look up - spoiler Charlie 2013-12-16 16:41:29 computer solution Charlie 2013-12-16 16:26:07 just look up - spoiler Ady TZIDON 2013-12-16 14:52:26

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