697

697 = 17 x 41.

697 is a heptagonal number.

697 is a cake number.

697 is a 12-hyperperfect number.

697 has two representations as a sum of two squares: 697 = 11² + 24² = 16² + 21².

697 is the hypotenuse of two primitive Pythagorean triples: 697² = 185² + 672² = 455² + 528².

Source: What's Special About This Number?