Fatto generale: 9910 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 9910 is the number of fixed 9-ominoes.
Trivia: 9910 is an uninteresting number.
Data storica: February 17th is the day in 1500 that Duke Friedrich and Duke Johann attempt to subdue the peasantry of Dithmarschen, Denmark, in the Battle of Hemmingstedt.