505

505 = 5 x 101.

505 has two representations as a sum of two squares: 505 = 8² + 21² = 12² + 19².

505 is the hypotenuse of two primitive Pythagorean triples: 505² = 217² + 456² = 336² + 377².

505³ = 59³ + 163³ + 499³, where 59, 163, and 499 are primes.

505 is the magic constant for a 10 x 10 normal magic square.

505 is the model number of a type of denim jeans produced by Levi Strauss & Co.

Source: Prime Curios!