1823

This number is a prime.

Leopold Kronecker (1823-1891) was famous for the quote "God made the natural numbers, all the rest is the work of man" (following his belief in an extreme form of mathematical constructivism now called finitism). [Caldwell]

Largest prime factor of 196884, the third coefficient of modular function j. [Pol]

The smallest non-palindromic balanced prime. [Angelini and Hasler]

The smallest prime p to contain the digits of π(p) which is also prime and one other prime digit. [Worrom]