Fatto generale: 2751 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 2751 is the number of ordered partitions of 21 into distinct parts.
Trivia: 2751 is an uninteresting number.
Data storica: July 13th is the day in 1174 that William I of Scotland, a key rebel in the Revolt of 1173–1174, is captured at Alnwick by forces loyal to Henry II of England.