Fatto matematico: 1866 is the number of inequivalent Ferrers graphs with 28 points.
Trivia: 1866 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: February 8th is the day in 1963 that the regime of Prime Minister of Iraq, Brigadier General Abdul-Karim Qassem is overthrown by the Ba'ath Party.