Fatto generale: 61500 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 61500 is a boring number.
Trivia: 61500 is an unremarkable number.
Data storica: May 18th is the day in 1812 that John Bellingham is found guilty and sentenced to death by hanging for the assassination of British Prime Minister Spencer Perceval.