1313

1313 = 13 x 101.

1313 is an evil number because it has an even number of 1s in its binary expansion: 10100100001.

1313 has two representations as a sum of two squares: 1313 = 17² + 32² = 23² + 28².

1313 is the hypotenuse of two primitive Pythagorean triples: 1313² = 255² + 1288² = 735² + 1088².

1313 is a divisor of 100⁶ - 1.

The starburst galaxy NGC 1313 is known as the Topsy-Turvy Galaxy.


The Italian poet Giovanni Boaccaccio was born in the year 1313.

Source: ESO
Image: (c) ESO