1717

1717 = 17 x 101.

1717 is a pentagonal number.

1717 has two representations as a sum of two squares: 1717 = 6² + 41² = 14² + 39².

1717 is the hypotenuse of two primitive Pythagorean triples: 1717² = 492² + 1645² = 1092² + 1325².

1717 is a divisor of 100⁸ - 1.

French mathematician and encylopaedist Jean le Rond d'Alembert was born on Nov. 16, 1717.

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Source: Number Gossip