2243

This number is a prime.

The smallest prime p such that p and the next 2 primes (2251, 2267) are all equal to 3 (mod 8). [Post]

2243 is the sum of the squares of three distinct primes (3^2 + 5^2 + 47^2). [Suzuki]

The only 4-digit prime whose the reversal is an oblong number, 3422=18*19, i.e., a number that can be represented as the product of two successive numbers. [Loungrides]

2243 = 32×34+33×35, using four consecutive numbers. [Leonardis]

The smallest prime number that is not the sum of all of the substrings of the digits of any other integer. [Gaydos]