607565706

This number is a composite.

A palindrome resulting from this "prime based" expression: (257 + ... + 607)² + (257² + ... + 607²). There are 57 consecutive primes inside each parentheses. Note that this palindrome starts with the last prime added: {607}565706. "57" appears also as a substring, 60756{57}06. The beast number {6}075{6}570{6} is included. [De Geest and Trotter]