perplexus.info :: Numbers : Double perfection

Double perfection (Posted on 2018-12-28)

Find the smallest integer for which both the number of its divisors and the sum of its prime factors are perfect numbers.

Rem: Duplicate primes are summed up: e.g. 12 = 2*2*3, - so the sum of 12's prime factors is 2+2+3=7.

Bonus question: Any others?

Submitted by Ady TZIDON

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Solution: (Hide)

ANSWER: 338
Bonus question: @OEIS A070311 Numbers n such that sopfr(n) and d(n) are both perfect numbers.

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	Subject	Author	Date
	computer solution	Charlie	2018-12-28 15:26:08

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