General fact: 2828 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 2828 is a value of n so that n(n+8) is a palindrome.
Trivia: 2828 is an unremarkable number.
Historical date: September 28th is the day in 1928 that Sir Alexander Fleming notices a bacteria-killing mold growing in his laboratory, discovering what later became known as penicillin.