# Factors of 15

A factor of 15 is a number that completely divides 15 with the remainder zero. Thus the factors of 15 are the divisors of 15. In this section, we will learn about the factors of 15 and the prime factors of 15.

#### Highlights of Factors of 15

• 15=3×5. This is the prime factorization of 15.
• The factors of 15 are 1, 3, 5 and 15.
• Prime factors of 15 are 3 and 5.
• Negative factors of 15 are –1, -3, -5 and –15.

#### What are the factors of 15?

Let us write the number 15 multiplicatively in all the possible ways.

15 = 1×15

15 = 3×5

As there are no numbers between 3 and 5 that can divide 15, so we will stop right now. So the factors of 15 in pairs are given as follows:

 15 = a×b Factors in Pairs (a,b) 15 = 1×15 (1, 15) 15 = 3×5 (3, 5)

Thus the pair factors of 15 are (1, 15) and (3, 5). As all the numbers appearing in pair factors are the factors of 15, we conclude that

 The factors of 15 are: 1, 3, 5 and 15.

#### Number of factors of 15

As the factors of 15 are 1, 3, 5 and 15, we see that the total number of factors of 15 is six.

#### Prime Factors of 15

Note that the factors of 15 are 1, 3, 5 and 15. Among those factors, we observe that only 3 and 5 are prime numbers as they do not have any proper divisors.

∴ the prime factors of 15 are 3 and 5.

#### How to find factors of 15?

Now we will determine the factors of 15 by division method. In this method, we will try to find the numbers that can divide 15 with no remainder. See that

15/1=15 and the remainder is 0.

1 and 15 are factors of 15.

15/3=5 and the remainder is 0.

3 and 5 are factors of 15.

Note that no numbers other than the numbers in violet color can divide 15. So the numbers in violet color, that is, 1, 3, 5 and 15 are the complete list of factors of 15.