Prime numbers are natural numbers greater than 1 that have exactly two distinct divisors: 1 and the number itself. In other words, a prime number can only be divided by 1 and itself without leaving a remainder.

For example:

• 2 is a prime number because its only divisors are 1 and 2.
• 3 is a prime number because its only divisors are 1 and 3.
• 4 is not a prime number because it has divisors other than 1 and 4 (specifically, 2).
• 5 is a prime number because its only divisors are 1 and 5.

Prime numbers are fundamental in number theory because any integer greater than 1 can be factored uniquely into prime numbers (this is called the prime factorization theorem).

Do you want more details on prime numbers or have any questions?

Here are five related questions to explore:

1. What is the difference between prime and composite numbers?
2. How do you find prime numbers using the Sieve of Eratosthenes?
3. What is the largest known prime number?
4. Why are prime numbers important in cryptography?
5. How can you prove whether a number is prime or not?

Tip: The number 2 is the only even prime number. All other even numbers can be divided by 2, so they are not prime.