Fait mathématique: 28231 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Culture générale: 28231 is an uninteresting number.
Date historique: April 16th is the day in 1941 that Bob Feller of the Cleveland Indians throws the only Opening Day no-hitter in the history of Major League Baseball, beating the Chicago White Sox 1-0.