4

4 (four) is a positive integer following 3 and preceding 5.

Properties

 * There are 4 seasons.
 * There are 4 directions.
 * There are 4 corners in a square.
 * 4 is equal to 2 squared.
 * 4 is the 2nd tetrahedral number.
 * 4 is the 2nd busy beaver number.