General fact: 9628 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 9628 is a boring number.
Trivia: 9628 is a boring number.
Historical date: May 11th is the day in 1970 that the Lubbock Tornado, a F5 tornado, hits Lubbock, Texas, killing 26 and causing $250 million in damage.