Fatto generale: 28917 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 28917 is an uninteresting number.
Trivia: 28917 is an unremarkable number.
Data storica: March 3rd is the day in 1924 that the 1400-year-old Islamic caliphate is abolished when Caliph Abdul Mejid II of the Ottoman Empire is deposed.