Fatto generale: 61409 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 61409 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Trivia: 61409 is an uninteresting number.
Data storica: February 17th is the day in 1871 that the victorious Prussian Army parades though Paris, France after the end of the Siege of Paris during the Franco-Prussian War.