Hecho general: 28505 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Hecho matemático: 28505 is an unremarkable number.
Trivia: 28505 is a boring number.
Fecha histórica: January 15th is the day in 1975 that the Alvor Agreement is signed, ending the Angolan War of Independence and giving Angola independence from Portugal.