5

The number five (5 in decimal form) is the sixth non negative number/natural number, the fifth positive integer, and the number preceding 6 and following 4 on the number line. It is the third prime number, meaning a group of five objects cannot be divided evenly into smaller groups.

It is easy to picture five objects in one's head, although it is not as easy as picturing 4, 1, 3, 2, or 0 objects.