General fact: 7751 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 7751 is a boring number.
Trivia: 7751 is an unremarkable number.
Historical date: March 21st is the day in 1999 that Bertrand Piccard and Brian Jones become the first to circumnavigate the Earth in a hot air balloon.