Fait mathématique: 53820 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Culture générale: 53820 is a boring number.
Date historique: May 9th is the day in 2004 that Chechen president Akhmad Kadyrov is killed by a land mine under a VIP stage during a World War II memorial victory parade in Grozny, Chechnya.