Fait général: 4891 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 4891 is a narcissistic number in base 5.
Culture générale: 4891 is an unremarkable number.
Date historique: May 22nd is the day in 1972 that Ceylon adopts a new constitution, thus becoming a Republic, changes its name to Sri Lanka, and joins the Commonwealth of Nations.