Fait mathématique: 85820 is an unremarkable number.
Culture générale: 85820 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Date historique: December 19th is the day in 1986 that Mikhail Gorbachev, leader of the Soviet Union, releases Andrei Sakharov and his wife from exile in Gorky.