Fait général: 9871 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fait mathématique: 9871 is the largest 4-digit prime with different digits.
Culture générale: 9871 is a boring number.
Date historique: January 9th is the day in 1861 that Mississippi becomes the second state to secede from the Union before the outbreak of the American Civil War.