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.

Table of Contents

## 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 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. |

**Must Read: **

Basic concepts of the factors of a number

## 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.

## Question-Answer on Factors of 15

**Question 1:** How to find the greatest common factor (GCF) of 12 and 15?

*Answer:*

The factors of 12 are 1, 2, 3, 4, 6 and 12.

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

So the common factors of 12 and 15 are 1 and 3 among which 3 is the greatest. That is, 3 is the greatest common factor of 12 and 15. In other words,

GCF(12, 15) = 3.

## FAQs on Factors of 15

**Q1: Find the factors of 15.**

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

**Q2: What are the prime factors of 15?**

Answer: 3 and 5 are the prime factors of 15.

This article is written by Dr. T. Mandal, Ph.D in Mathematics. On Mathstoon.com you will find Maths from very basic level to advanced level. Thanks for visiting.