Factors of 391 are the list of integers that we can split evenly into 391. There are 4 factors of 391, which are 1, 17, 23, 391. Here, 391 is the biggest factor. The Prime Factors and Pair Factors of 391 are 17 × 23 and (1, 391), (17, 23) respectively.

• All Factors of 391: 1, 17, 23 and 391
• Negative Factors of 391: -1, -17, -23 and -391
• Prime Factors of 391: 17, 23
• Prime Factorization of 391: 17¹ × 23¹
• Sum of Factors of 391: 432

1.	What Are the Factors of 391?
2.	Factors of 391 by Prime Factorization
3.	Factors of 391 in Pairs
4.	FAQs on Factors of 391

Factors of 391 are pairs of those numbers whose products result in 391. These factors are either prime numbers or composite numbers.

How to Find the Factors of 391?

To find the factors of 391, we will have to find the list of numbers that would divide 391 without leaving any remainder.

• 391/23 = 17; therefore, 23 is a factor of 391 and 17 is also a factor of 391.
• 391/1 = 391; therefore, 1 is a factor of 391 and 391 is also a factor of 391.

Similarly we can find other factors. Hence, the factors of 391 are 1, 17, 23, 391.

☛ Also Check:

• Factors of 128 - The factors of 128 are 1, 2, 4, 8, 16, 32, 64, 128
• Factors of 39 - The factors of 39 are 1, 3, 13, 39
• Factors of 65 - The factors of 65 are 1, 5, 13, 65
• Factors of 19 - The factors of 19 are 1, 19
• Factors of 98 - The factors of 98 are 1, 2, 7, 14, 49, 98

The number 391 is composite and therefore it will have prime factors. Now let us learn how to calculate the prime factors of 391. The first step is to divide the number 391 with the smallest prime factor, here it is 17. We keep dividing until it gives a non-zero remainder.

• 391 ÷ 17 = 23

Further dividing 23 by 17 gives a non-zero remainder. So we stop the process and continue dividing the number 23 by the next smallest prime factor. We stop ultimately if the next prime factor doesn't exist or when we can't divide any further.

So, the prime factorization of 391 can be written as 17¹ × 23¹ where 17, 23 are prime.

Pair factors of 391 are the pairs of numbers that when multiplied give the product 391. The factors of 391 in pairs are:

• 1 × 391 = (1, 391)
• 17 × 23 = (17, 23)

Negative pair factors of 391 are:

• -1 × -391 = (-1, -391)
• -17 × -23 = (-17, -23)

NOTE: If (a, b) is a pair factor of a number then (b, a) is also a pair factor of that number.