717

This number is a composite.

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

A curious palindrome whose splitting up into parts 7 and 17 is interpretable in two ways. First as 'the 7th prime is 17' and secondly as 'the sum of the primes up to 7 is 17'. No larger palindrome is known having this two-fold property. [De Geest and Rosa]

The sum of the squares of the 717 consecutive primes starting from 1847 and 6959 is (in both cases) palindromic (18708380781 and 77817671877). [De Geest]