Fatto generale: 2663 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 2663 is the number of digits of the 20^{th} perfect number.
Trivia: 2663 is an uninteresting number.
Data storica: April 16th is the day in 1945 that the United States Army liberates Nazi Sonderlager (high security) prisoner-of-war camp Oflag IV-C (better known as Colditz).