1657

This number is a prime.

1657 = prime( (1*6*5*7) + (1+6+5+7) ) + (1*6*5*7). Note that the prime 1657 is the only number less than 10^7 with this property. [Firoozbakht]

Math historian and philosopher Bernard de Fontenelle was born in 1657.

Eight consecutive prime digits occur immediately following position 1657 (after the decimal point) of π. [Johnson]

The Hardy-Ramanujan number was actually discovered by Bernard Frénicle de Bessy in 1657. [Olry]