Fait général: 2811 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 2811 is the number of inequivalent Ferrers graphs with 30 points.
Culture générale: 2811 is a boring number.
Date historique: September 11th is the day in 1941 that Charles Lindbergh's Des Moines Speech accusing the British, Jews and the Roosevelt administration of pressing for war with Germany.