1233

1233 = 3² x 137.

1233 has a representation as a sum of two squares: 1233 = 12² + 33². 1233 is the smallest 2n-digit number that is the sum of the squares of its n-digit halves.

1233 is a value of n such that n² - 2 and n² + 2 are both prime: 1,520,287 and 1,520,291.

1233 is a Happy-Go-Lucky number (both Happy and Lucky).


Southern Pacific steam locomotive 1233 was built in 1918 by the Baldwin Locomotive Works in Pennsylvania.

Source: Number Gossip