Fatto generale: 9997 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 9997 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Trivia: 9997 is a boring number.
Data storica: May 15th is the day in 1252 that Pope Innocent IV issues the papal bull ad exstirpanda, which authorizes, but also limits, the torture of heretics in the Medieval Inquisition.