Fatto generale: 9791 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 9791 is an uninteresting number.
Trivia: 9791 is a boring number.
Data storica: October 21st is the day in 1987 that Jaffna hospital massacre is carried out by Indian Peace Keeping Force in Sri Lanka killing 70 ethnic Tamil patients, doctors and nurses.