Seventeen is the number that comes after sixteen and before eighteen. It's written as 17 in numerals and represents one ten and seven ones.

Seventeen is often seen as an age when teenagers are almost adults but not quite there yet. In the United States, many seventeen-year-olds can get their driver's license, giving them new freedom and responsibility. They're old enough to work jobs and make important decisions, but still young enough to be figuring out who they want to be.

The number itself is a prime number, which means it can only be divided evenly by one and itself. Mathematicians find seventeen interesting for this reason. In sports, the number seventeen appears on jerseys, and some athletes consider it lucky.

When someone talks about their sweet seventeen birthday, they're celebrating this in-between time of growing up. You might use it in a sentence like: “There were seventeen students in the chess club this year.”