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Prime with no prime digits (Posted on 2017-04-25) Difficulty: 2 of 5
Find the smallest prime containing every non-prime digit.

See The Solution Submitted by Ady TZIDON    
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BTW, why there are no 5's Comment 5 of 5 |
(In reply to re(2): solution via computer -my remarks by Charlie)

In the first 100 numbers having all of the non-prime digits, the interloping primes can occur only in the 7-digit numbers as we haven't arrived at 8-digit numbers yet. The interloping prime can only be 3 or 7 and not 5, as the non-primes, 0, 1, 4, 6, 8 and 9, add up to 28 and the addition of 5 would make 33, so all such numbers would be a multiple of 3 and therefore not prime. You'd have to get into the 8-digit numbers, with either a repetition of a non-prime, or another prime (or a second 5) to get a case with all the primes and also at least one 5.
  Posted by Charlie on 2017-04-28 15:38:57

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