All composite numbers can be expressed as unique products of prime numbers. This is accomplished by dividing the original number and its factors by prime numbers until all the factors are prime. A factor tree can help you visualize this.
Example: 210
210 Divide by two.
105,2 Divide by three.
35,3,2 Divide by five.
7,5,3,2 Stop. All the factors are prime.
2 x 3 x 5 x 7 = 210
That's the prime factorization of 210.
Chat with our AI personalities
But you do know the factors of prime numbers. Every prime number has two factors: one and the number itself.
You know that 7 is a prime number because it only has two factors.
Prime numbers only have two factors.
A prime number has no factors other than 1 and the number itself. If prime factorization of a number reveals one or more additional prime factors, the number is a composite.
To know that a number is prime you need to know that it has no factors other than 1 and the number itself.To know that a number is composite you only need to know one factor other than the number itself or 1.