71

This number is a prime.

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

Jeffery Marshall © 2002

The smallest prime that remains prime when inserting one, two, three, or four zeros between each digit. [Capelle]

The largest known natural number n such that 2ⁿ does not contain the prime digit 5. It is also the case for the prime digit 7. [Capelle]

The largest known positive integer n for which the sum of all primes smaller or equal to n divides the sum of all nonprimes smaller or equal to n. It's also the largest known positive integer n for which this sum of primes divides n(n+1)/2. Moreover, it's the only known case where n divides all these numbers. [Capelle]