prime number
Sign in to savepositive integer with exactly two divisors, 1 and itself
AI overview
A prime number is a positive integer that can only be divided evenly by 1 and itself, such as 2, 3, 5, or 7. Prime numbers are fundamental building blocks in mathematics because every other positive integer can be expressed as a product of primes, making them essential to understanding number structure and important for applications like encryption.
AI-generated from the Wikipedia summary — may contain errors.
Article
Composite numbers can be arranged into rectangles but prime numbers cannot.
A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime because the only ways of writing it as a product, 1 × 5 or 5 × 1, involve 5 itself. However, 4 is composite because it is a product (2 × 2) in which both numbers are smaller than 4. Primes are central in number theory because of the fundamental theorem of arithmetic: every natural number greater than 1 is either a prime itself or can be factorized as a product of primes that is unique up to their order.