9

9 is the integer succeeding 8 and preceding 10.

properties
9 = 3^2

9 is the smallest odd composite number

9 is the larger of two bi-unitary superperfect numbers

All integers are the sum of at most 9 cubes

A number is divisible by 9 if its digital root is 9

A 9 sided polygon is called an enneagon or nonagon