What Are Prime Numbers?

A prime number is a positive integer greater than 1 that has no positive integer divisors other than 1 and itself. For example, 2, 3, 5, and 7 are prime numbers, but 4, 6, 8, and 9 are not.

To determine if a number is prime, we can divide it by every positive integer that is less than the number and greater than 1. If the number is not divisible by any of these integers, it is a prime number. For example, to determine if 7 is a prime number, we can divide it by 2, 3, 4, 5, and 6. Since 7 is not divisible by any of these numbers, it is a prime number.

Prime numbers are important in mathematics and have many applications in cryptography and other fields. They are also of great interest to mathematicians because of their unique properties and the challenges they pose in solving problems involving them.