Fatto matematico: 990 is a triangular number that is the product of 3 consecutive integers.
Trivia: 990 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: September 16th is the day in 1961 that the United States National Hurricane Research Project drops eight cylinders of silver iodide into the eyewall of Hurricane Esther.