**A** prime number is any positive integer greater than zero that has only two proper divisorsA proper divisor is a number *n* that when divided into another number ^{[a]}One is not a prime number because it has only one proper divisor, itself. numbers greater than 1 that are not prime are known as composite numbers, because they can be expressed as the product of two other numbers smaller than themselves;^{[1]} for instance, 8 can be expressed as . (The prime factor of 8 is )

Prime numbers are fundamental to mathematics, as all whole numbers can be constructed from them; anything that can be shown to be true about prime numbers is therefore true for all numbers.^{[2]}

## Citations

## Bibliography

*Closing the Gap: The Quest to understand Prime Numbers*(ebook). Oxford University Press.

## Notes

a. | ^ | One is not a prime number because it has only one proper divisor, itself. |