Fatto generale: 28013 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 28013 is an unremarkable number.
Trivia: 28013 is an uninteresting number.
Data storica: September 10th is the day in 2001 that Charles Ingram cheats his way into winning one million pounds on a British version of Who Wants to be a Millionaire.