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Phrase a question I (Posted on 2015-02-16) Difficulty: 2 of 5
This number, a sum of 6 consecutive primes, has exactly 8 divisors.

Rem: Jeopardy style answer needs a question.

No Solution Yet Submitted by Ady TZIDON    
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What is 56, Alex?

56 = 3+5+7+11+13+17 and is divided by 1,2,4,7,8,14,28,56.

I have no idea if 56 is unique.    

If a,b,c . . . are the exponents of the prime factors of the sought for number then the number of divisors = (a+1)*(b+1)*(c+1) . . . 

8 divisors require either (a,b,c) = (1,1,1) or (a,b) = (3,1).  I checked for a cubic factor first since it looked easier. 

  Posted by xdog on 2015-02-16 08:21:11
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