Fatto generale: 28309 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 28309 is an unremarkable number.
Trivia: 28309 is an unremarkable number.
Data storica: July 3rd is the day in 1938 that President Franklin D. Roosevelt dedicates the Eternal Light Peace Memorial and lights the eternal flame at Gettysburg Battlefield.