23 is one of only two integers that needs nine (positive) cubes to represent it: 23 = 23 + 23 + 13 + 13 + 13 + 13 + 13 + 13 + 13.
There were 23 problems on David Hilbert’s list of unsolved mathematical problems, presented to the International Congress of Mathematicians in Paris in 1900.
For 23 or more people in a room, the probability that two people have the same birthday is greater than 50%.
23! is 23 digits long.
The speed limit on campus at Tulane University.
Sources: Number Gossip; Wikipedia
Photo: M. Pearson