Fatto generale: 66091 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 66091 is a boring number.
Trivia: 66091 is an unremarkable number.
Data storica: December 12th is the day in 1787 that Pennsylvania becomes the second state to ratify the United States Constitution five days after Delaware became the first.