# Factors of 391

Factors of 391 are 1, 17, 23, and 391

#### How to find factors of a number

 1.   Find factors of 391 using Division Method 2.   Find factors of 391 using Prime Factorization 3.   Find factors of 391 in Pairs 4.   How can factors be defined? 5.   Frequently asked questions 6.   Examples of factors

### Example: Find factors of 391

• Divide 391 by 1: 391 ÷ 1 : Remainder = 0
• Divide 391 by 17: 391 ÷ 17 : Remainder = 0
• Divide 391 by 23: 391 ÷ 23 : Remainder = 0
• Divide 391 by 391: 391 ÷ 391 : Remainder = 0

Hence, Factors of 391 are 1, 17, 23, and 391

#### 2. Steps to find factors of 391 using Prime Factorization

A prime number is a number that has exactly two factors, 1 and the number itself. Prime factorization of a number means breaking down of the number into the form of products of its prime factors.

There are two different methods that can be used for the prime factorization.

#### Method 1: Division Method

To find the primefactors of 391 using the division method, follow these steps:

• Step 1. Start dividing 391 by the smallest prime number, i.e., 2, 3, 5, and so on. Find the smallest prime factor of the number.
• Step 2. After finding the smallest prime factor of the number 391, which is 17. Divide 391 by 17 to obtain the quotient (23).
391 ÷ 17 = 23
• Step 3. Repeat step 1 with the obtained quotient (23).
23 ÷ 23 = 1

So, the prime factorization of 391 is, 391 = 17 x 23.

#### Method 2: Factor Tree Method

We can follow the same procedure using the factor tree of 391 as shown below:

So, the prime factorization of 391 is, 391 = 17 x 23.

#### 3. Find factors of 391 in Pairs

Pair factors of a number are any two numbers which, which on multiplying together, give that number as a result. The pair factors of 391 would be the two numbers which, when multiplied, give 391 as the result.

The following table represents the calculation of factors of 391 in pairs:

Factor Pair Pair Factorization
1 and 391 1 x 391 = 391
17 and 23 17 x 23 = 391

Since the product of two negative numbers gives a positive number, the product of the negative values of both the numbers in a pair factor will also give 391. They are called negative pair factors.

Hence, the negative pairs of 391 would be ( -1 , -391 ) , ( -17 , -23 ) .

#### How can we define factors?

In mathematics a factor is a number which divides into another without leaving any remainder. Or we can say, any two numbers that multiply to give a product are both factors of that product. It can be both positive or negative.

#### Properties of factors

• Every number is a factor of zero (0), since 391 x 0 = 0.
• Every number other than 1 has at least two factors, namely the number itself and 1.
• Every factor of a number is an exact divisor of that number, example 1, 17, 23, 391 are exact divisors of 391.
• Factors of 391 are 1, 17, 23, 391. Each factor divides 391 without leaving a remainder.

• Is 391 a perfect square?

No 391 is not a perfect square.

• What are factors of 391?

Factors of 391 are 1, 17, 23, 391.

• Which is greatest factor of 391?

The greatest factor of 391 is 23.

• What is the sum of all factors of 391?

The sum of all factors of 391 is 432.

• What are multiples of 391?

First five multiples of 391 are 782, 1173, 1564, 1955.

• What is the greatest prime factors of 391?

The greatest prime factor of 391 is 23.

• What are six multiples of 391?

First five multiples of 391 are 782, 1173, 1564, 1955, 2346, 2737.

• What is prime factorization of 391?

Prime factorization of 391 is 17 x 23.

• Is 391 a whole number?

Yes 391 is a whole number.

#### Examples of Factors

Annie's mathematics teacher has asked her to find out all the positive and negative factors of 391? Help her in writing all the factors.

Positive factors are 1, 17, 23, 391.
Negative factors are -1, -17, -23, -391.

Can you help Sammy find out the product of the odd factors of 391?

Factors of 391 are 1, 17, 23, 391.
Odd factors of 391 are 1, 17, 23, 391.
Hence product of odd factors of 391 is; 1 x 17 x 23 x 391 = 152881.

Joey wants to write all the prime factors of 391 in exponential form, but he doesn't know how to do so can you assist him in this task?

Prime factors of 391 are 17, 23.
So in exponential form it can be written as 17 x 23.

How many factors are there for 391?

Factors of 391 are 1, 17, 23, 391.
So there are in total 4 factors.

Kevin has been asked to write 3 factor(s) of 391. Can you predict the answer?

3 factor(s) of 391 are 1, 17, 23.

Sammy is puzzled while calculating the prime factors of 391. Can you help him find them?

Factors of 391 are 1, 17, 23, 391.
Prime factors of 391 are 17, 23

What is prime factorization of 391?

Prime factorization of 391 is 17 x 23 = 17 x 23.