# 1619

This number is a prime.

A prime whose cube can be expressed as the sum of three prime squares in two different ways, i.e., 1619^{3} is 3^{2} + 24967^{2} + 60169^{2} and 3^{2} + 28163^{2} + 58741^{2}. [Rivera]

Kepler's 3rd Law of planetary motion wasn't published until 1619.

The smallest nonprime-digit emirp that remains a nonprime-digit emirp when each digit is replaced by its complement (9491). Note that it is also the smallest nonprime-digit emirp that remains an emirp when sandwiched between a pair of prime digits (316193) and that the sum of digits is prime in all cases. [Beedassy]

Exactly half of the first 3238 positive integers (1619) contain no twos. [Gaydos]

1619 is the 256th prime. If you square the number formed from the first two digits in ascending order, namely 16, you get 256. [Missailidis]