9631

This number is a prime.

The larger of only two 4-digit primes (emirps) p such that 10^100+p is prime. [Loungrides]

The largest 4-digit distinct-digit prime that yields another when each digit d is repeated d times, i.e., 9999999996666663331. [Loungrides]

The largest 4-digit prime whose the reversal is the square of an emirp, i.e., 1369=37^2. [Loungrides]

9631 is the start of the smallest set of four consecutive primes {9631, 9643, 9649, 9661} that are also consecutive lucky numbers. [Rivera]