General fact: 51808 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 51808 is an unremarkable number.
Trivia: 51808 is an uninteresting number.
Historical date: November 4th is the day in 1970 that Genie, a 13-year-old feral child is found in Los Angeles, California having been locked in her bedroom for most of her life.