Hecho general: 84211 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Hecho matemático: 84211 is an uninteresting number.
Trivia: 84211 is an unremarkable number.
Fecha histórica: July 24th is the day in 1701 that Antoine de la Mothe Cadillac founds the trading post at Fort Pontchartrain, which later becomes the city of Detroit, Michigan.