Prime Numbers

References & Edit History Related Topics

Images

Cast iron house number seven mounted on a black plaque above a red and wood-paneled door.

Form page titled “Is it a prime number?” showing an input box labeled “Enter a number between 0 and 1,000,000.” and a green “Check” button.

Prime Numbers: Media

Prime numbers are simple to define but have endless complexity.

Images

Cast iron house number seven mounted on a black plaque above a red and wood-paneled door.

Prime number

The number 7 is a prime number, meaning it can be divided only by 1 and itself.

© Rafael Croonen/Shutterstock.com

Interactives

Form page titled “Is it a prime number?” showing an input box labeled “Enter a number between 0 and 1,000,000.” and a green “Check” button.

Is it a prime number?

Test your math smarts: enter any number up to 1,000,000 and find out if it's prime.

Encyclopædia Britannica, Inc.