3797

This number is a prime.

3797 is the only four-digit prime, in which: i.The first digit and the last digit are primes (3,7). ii.The first two-digit number, the second two-digit number and the third two-digit number are primes (37,79,97). iii.The first and the last three-digit numbers are primes (379,797). [Sreechakra]