Fatto generale: 1831 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 1831 is the smallest prime that is followed by 15 composite numbers.
Trivia: 1831 is a boring number.
Data storica: January 4th is the day in 1974 that United States President Richard Nixon refuses to hand over materials subpoenaed by the Senate Watergate Committee.