Eighteen is a composite number, its proper divisors being 1, 2, 3, 6 and 9.
18 is the age limit for being allowed a driver's license in many parts of the world.
... any race. There are 145 households out of which 38.6% have children under the age of 18 living with them, 74.5% are married couples living together, 8.3% have a female ...