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Number Theory
Level
2
What is the smallest prime number of which the sum of the digits is odd and not prime?
The answer is 997.
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1 solution
Because we search a prime number the sum of digits can’t be divisible by three. Also, it is stated odd And not a prime number. The smallest possible sum of digits is hence 25. Trying all number smaller than 100 with that sum then gives you the correct answer, 997.