900

900 = 2² x 3² x 5².

900 is a square number: 30 x 30 = 900.

900 is the smallest square that is the sum of different primes by using all ten digits: 900 = 503 + 241 + 89 + 67 = 509 + 283 + 61 + 47.

900 has a base 5 representation (12100) that begins with its base 9 representation (1210). Its base 7 representation is 2424.

900 has a representation as a sum of two squares: 900 = 18² + 24².


900 is the sum (in degrees) of the internal angles of a heptagon.

Source: Prime Curios!