Fait mathématique: 1855 is the number of permutations of 7 items that fix 1 element.
Culture générale: 1855 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Date historique: January 28th is the day in 1964 that an unarmed USAF T-39 Sabreliner on a training mission is shot down over Erfurt, East Germany, by a Soviet MiG-19.