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SUM = PR0DUCT (Posted on 2017-10-18) Difficulty: 3 of 5
List all the integers N, below 10000, such that the sum of their proper divisors (i.e. N excluded) equals their product.

Counterexample:
take 12: s(1,2,3,4,6)=16; p(1,2,3,4,6)=144;
so 12 is not on the list.

  Submitted by Ady TZIDON    
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Solution: (Hide)
The list consists of number 6 and all prime numbers.
See Brian Smith's proof.

Comments: ( You must be logged in to post comments.)
  Subject Author Date
Hints/Tipsre: Analytic Solution..............revisedAdy TZIDON2017-10-19 23:07:03
SolutionAnalytic SolutionBrian Smith2017-10-18 12:02:57
Solutioncomputer solutionCharlie2017-10-18 10:52:00
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