Fait mathématique: 5909 is the number of symmetric plane partitions of 32.
Culture générale: 5909 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Date historique: March 5th is the day in 1960 that Alister Hardy publicly announces his idea that ape-human divergence may have been due to a coastal phase, giving rise to the Aquatic Ape Hypothesis.