Fatto matematico: 5383 is the number of triangles of any size contained in the triangle of side 27 on a triangular grid.
Trivia: 5383 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: September 26th is the day in 1908 that Ed Reulbach becomes the first and only pitcher to throw two shutouts in one day against the Brooklyn Dodgers.