Fatto generale: 880 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 880 is the number of 4×4 magic squares.
Trivia: 880 is an uninteresting number.
Data storica: May 29th is the day in 1790 that Rhode Island becomes the last of the original United States' colonies to ratify the Constitution and is admitted as the 13th U.S. state.