Fatto generale: 2660 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 2660 is a boring number.
Trivia: 2660 is an uninteresting number.
Data storica: April 13th is the day in 1256 that the Grand Union of the Augustinian order formed when Pope Alexander IV issues a papal bull Licet ecclesiae catholicae.