33, XXXIII, thirty-three

33 is the largest positive integer that can not be expressed as a sum of different triangular numbers.
Jesus's age when he was crucified in 33 A.D., according to many, though not verified historically.
The number of innings played in the longest baseball game in history.
Jersey number of retired baseball star José Canseco.
Alexander the Great died at the age of thirty-three.
The code for international direct-dial phone calls to France.
A significant number in modern numerology, one of the master numbers along with 11 and 22.