Fatto generale: 28215 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 28215 is an uninteresting number.
Trivia: 28215 is an unremarkable number.
Data storica: March 31st is the day in 1854 that Commodore Matthew Perry signs the Treaty of Kanagawa with the Japanese government, opening the ports of Shimoda and Hakodate to American trade.