3773257

This number is a prime.

The smallest prime-digit prime concatenated from first n multidigit Pierpont primes, (n=3), i.e., 37, 73, 257. A Pierpont prime is a prime of form 2^t*3^u + 1. Note that 37=2^2*3^2+1, 73=2^3*3^2+1, 257=2^8*3^0+1. [Loungrides]