Fatto generale: 5219 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 5219 is an unremarkable number.
Trivia: 5219 is an unremarkable number.
Data storica: April 15th is the day in 1989 that Upon Hu Yaobang's death, the Tiananmen Square protests of 1989 begin in the People's Republic of China.