Factors of 391: Prime Factorization, Methods, and Examples

The numbers that produce the remainder zero when divided by the actual number, are called Factors. The factors of the given number can be positive and negative, provided that the given number is obtained after taking the product of two integers. 

Factors Of 391

More details about the factorization of 391 are given in the article.

Factors of 391

Here are the factors of number 391.

Factors of 391: 1, 17, 23, 391

Negative Factors of 391

The negative factors of 391 are similar to its positive aspects, just with a negative sign.

Negative Factors of 391: -1, -17, -23, -391

Prime Factorization of 391

The prime factorization of 391 is the way of expressing its prime factors in the product form.

Prime Factorization: 17 x 23

In this article, we will learn about the factors of 391 and how to find them using various techniques such as upside-down division, prime factorization, and factor tree.

What Are the Factors of 391?

The factors of 391 are 1, 17, 23, and 391. These numbers are the factors as they do not leave any remainder when divided by 391.

The factors of 391 are classified as prime numbers and composite numbers. The prime factors of the number X can be determined using the prime factorization technique.

How To Find the Factors of 391?

You can find the factors of 391 by using the rules of divisibility. The divisibility rule states that any number, when divided by any other natural number, is said to be divisible by the number if the quotient is the whole number and the resulting remainder is zero.

To find the factors of 391, create a list containing the numbers that are exactly divisible by 391 with zero remainders. One important thing to note is that 1 and 391 are the 391’s factors as every natural number has 1 and the number itself as its factor.

1 is also called the universal factor of every number. The factors of 391 are determined as follows:

\[\dfrac{391}{1} = 391\]

\[\dfrac{391}{17} = 23\]

\[\dfrac{391}{391} = 1\]

Therefore, 1, 17, 23, and 391 are the factors of 391.

Total Number of Factors of 391

For 391, there are 4 positive factors and 4 negative ones. So in total, there are 8 factors of 391. 

To find the total number of factors of the given number, follow the procedure mentioned below:

  1. Find the factorization/prime factorization of the given number.
  2. Demonstrate the prime factorization of the number in the form of exponent form.
  3. Add 1 to each of the exponents of the prime factor.
  4. Now, multiply the resulting exponents together. This obtained product is equivalent to the total number of factors of the given number.

By following this procedure, the total number of factors of 391 is given as:

Factorization of 391 is 17 x 23.

The exponent of 17, and 23 is 1.

Adding 1 to each and multiplying them together results in 8.

Therefore, the total number of factors of 391 is 8. 4 are positive, and 4 factors are negative.

Important Notes

Here are some essential points that must be considered while finding the factors of any given number:

  • The factor of any given number must be a whole number.
  • The factors of the number cannot be in the form of decimals or fractions.
  • Factors can be positive as well as negative.
  • Negative factors are the additive inverse of the positive factors of a given number.
  • The factor of a number cannot be greater than that number.
  • Every even number has 2 as its prime factor, the smallest prime factor.

Factors of 391 by Prime Factorization

The number 391 is a composite number. Prime factorization is a valuable technique for finding the number’s prime factors and expressing the number as the product of its prime factors.prime factorization of 391

Before finding the factors of 391 using prime factorization, let us find out what prime factors are. Prime factors are the factors of any given number that are only divisible by 1 and themselves.

To start the prime factorization of 391, start dividing by its most minor prime factor. First, determine that the given number is either even or odd. If it is an even number, then 2 will be the smallest prime factor.

Continue splitting the quotient obtained until 1 is received as the quotient. The prime factorization of 391 can be expressed as:

391 = 17 x 23

Factors of 391 in Pairs

The factor pairs are the duplet of numbers that, when multiplied together, result in the factorized number. Factor pairs can be more than one depending on the total number of factors given.Factors of 391 in Pairs

For 391, the factor pairs can be found as:

1 x 391 = 391

17 x 23 = 391 

The possible factor pairs of 391 are given as (1, 391) and (17, 23 ).

All these numbers in pairs, when multiplied, give 391 as the product.

The negative factor pairs of 391 are given as:

-1 x -391 = 391 

-17 x -23 = 391

It is important to note that in negative factor pairs, the minus sign has been multiplied by the minus sign, due to which the resulting product is the original positive number. Therefore, –1, -17, -23, and -391 are called negative factors of 391.

The list of all the factors of 391, including positive as well as negative numbers, is given below.

Factor list of 391: 1, -1, 17, -17, 23, -23, 391, and -391

Factors of 391 Solved Examples

To better understand the concept of factors, let’s solve some examples.

Example 1

How many factors of 391 are there?


The total number of Factors of 391 is 8.

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

Example 2

Find the factors of 391 using prime factorization.


The prime factorization of 391 is given as:

391 $\div$ 23 = 17 

17 $\div$ 17 = 1 

So the prime factorization of 391 can be written as:

17 x 23 = 391

Factors of 390|Factors List| Factors of 392