Fatto generale: 51404 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 51404 is an uninteresting number.
Trivia: 51404 is an unremarkable number.
Data storica: September 26th is the day in 2009 that Typhoon Ketsana (2009) hit the Philippines, China, Vietnam, Cambodia, Laos and Thailand, causing 700 fatalities.