Fatto generale: 4391 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 4391 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Trivia: 4391 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: January 8th is the day in 1906 that a landslide in Haverstraw, New York, caused by the excavation of clay along the Hudson River, kills 20 people.