495

495 = 3² x 5 x 11.

495 is the Kaprekar constant for three-digit numbers. Arrange the digits of any three-digit number whose digits are not all the same in descending and ascending order, compute the difference, then repeat the process. For example: 311 - 113 = 198; 981 - 189 = 792; 972 - 279 = 693; 963 - 369 = 594; 954 - 459 = 495.

495 is the ninth pentatope number.

495 is a number that cannot be written as a sum of three squares.

Interstate 495 (Capital Beltway) is a highway that surrounds Washington, D.C.

Source: Wolfram MathWorld