[Mathematics] Prime Numbers and Composite Numbers

Overview

This post covers the concepts of prime numbers and composite numbers.

Summary

1. Natural Numbers

1.1. The Number 1

• 1 is neither a prime number nor a composite number.

1.2. Prime Numbers

• A prime number is a natural number greater than 1 that has no divisors other than 1 and itself.
• It has exactly 2 divisors.
• 2 is the only even prime number and the smallest prime number.
• Prime numbers can be easily found using the Sieve of Eratosthenes.

1.3. Composite Numbers

• A composite number is a natural number greater than 1 that is not a prime number.
• It has 3 or more divisors.