163

This number is a prime.

Just showing those entries submitted by 'Vrba': (Click here to show all)

+ Let the cs(p) be the cumulative digit sum of all the primes 2 to p (e.g., cs(11)=2+3+5+7+1+1=19). There are the only four known primes such that cs(p)=2p; they are 5, 23, 47 and 163. [Vrba]

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