A composite number is a positive integer that can be factored as a product of two or more prime numbers. Every integer except one and zero is either a prime number or a composite number. The integer 14 is a composite number because it can be factored as 2 × 7.
Properties
- All even numbers greater than 2 are composite numbers.
- All composite numbers are non-primes.
- The smallest composite number is 4.
- One has
for all composite numbers 
greater than 4 (Wilson's theorem).
- Also,
for all composite numbers greater than 4 (composite theorem).