Hecho general: 53211 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Hecho matemático: 53211 is an unremarkable number.
Trivia: 53211 is a boring number.
Fecha histórica: September 7th is the day in 1895 that the first game of what would become known as rugby league football is played, in England, starting the 1895–96 Northern Rugby Football Union season.