208

This number is a composite.

208 = 2² + 3² + 5² + 7² + 11². [Sladcik]

208^0 + 208^1 + 208^2 + 208^3 + ... + 208^35 + 208^36 is a prime number. [Raghava]

Smallest positive integer k>=2 such that no primes of the form (k+1)*k^n-1 with positive integer n are known. [Luen]