Fait général: 17811 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 17811 is an uninteresting number.
Culture générale: 17811 is a boring number.
Date historique: October 5th is the day in 869 that the Fourth Council of Constantinople is convened to decide about what to do about patriarch Photius of Constantinople.