Fatto matematico: 9854 is the index of a triangular number containing only 3 different digits.
Trivia: 9854 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: December 23rd is the day in 1982 that the United States Environmental Protection Agency announces it has identified dangerous levels of dioxin in the soil of Times Beach, Missouri.