18 (eighteen) is the natural number following 17 and preceding 19.
It is a largely composite number,[2] as it has 6 divisors and no smaller number has more than 6 divisors.
In the classification of finite simple groups, there are 18 infinite families of groups.
[3] In most countries, 18 is the age of majority, in which a minor becomes a legal adult.
Many websites restrict adult content to visitors who claim to be at least 18 years old.