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Anyway (Posted on 2010-08-16) Difficulty: 2 of 5
A three digit number N remains prime, no matter how you permute its digits.

Find N.

See The Solution Submitted by Ady TZIDON    
Rating: 4.0000 (1 votes)

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Solution solution | Comment 1 of 4
All multi-digit primes must end in 1, 3, 7 or 9. For a three-digit number in all its three-digital permutations to remain prime, the three digits must be composed of 2 or 3 of these given digits.
There are three sets of such primes:
(113, 131, 311), (199, 919, 991), and (337, 373, 733).
  Posted by Dej Mar on 2010-08-16 12:22:49
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