Factors of 155
2026-02-28 01:10 Diff
https://brightchamps.com/en-us/math/numbers/factors-of-155

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Last updated on December 11, 2025

A factor is a number that divides another number evenly without any remainder. We use factors for arranging items or dividing quantities evenly. Let’s learn and see what are the factors of 155.

What are the factors of 155?

Every number, except 1 and 0, will have a minimum of 2 factors. 


Factors of 155: 1,155, 5, 31
Negative factors of 155: -1,-155,-5,-31
Prime factorization of 155: 5×31
Sum of factors: 1+155+5+31=192
 

How to find the factors of 155?

The methods mentioned below can be used to find the factors of 155. Use any factor-finding method that is easy for you. 


— Multiplication method 
— Division method 
— Prime factorization and prime factors method
— Factor tree method
 

Finding Factors Using Multiplication

Find the pair of numbers which when multiplied gives 155.


155 is a composite number because it has more than 2 factors.


The factor pairs of 155 are


Positive factor pairs : (1,155) (5,31) 
Negative factor pairs : (-1,-155) (-5,-31)

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Finding Factors by Division Method

Start dividing 155 with small numbers and check the remainder.


Dividend = Divisor x Quotient + Remainder


The factors of 155 are 1,5,31,155 and -1,-5,-31,-155.
 

Prime Factors and Prime Factorization

  • Prime factors of 155: 5,31
  • The prime factorization of 155= 5×31
  • The positive factors of 155 are 1,5,31,155. The negative factors are -1,-155,-5,-31.
     

Factor tree

Factor tree is a graphical representation of breaking down any number into prime factors.


In case of 155, 


Step 1: First, we write the number on top (in this case, 155). From there, it will be broken down into 2 parts.


Step 2: Fill in the factor pairs of 155 in separate steps. In this step, the number will be factorized into 5 and 31.


Step 3: From this we can find that the prime factors of 5 and 31. This is how the factor tree helps students visualize the factors more easily.
 

Factor Pairs

Factor pairs are a combination of two numbers, a and b, whose product is equal to 155. So, over here, a and b are a factor pair of 155.


The factor pairs of 155 are


Positive factor pairs -- (1,155) (5,31) 
Negative factor pairs -- (-1,-155) (-5,-31)

Common mistakes and how to avoid them in the factors of 155

It can get really tricky when trying to learn factors, and there is nothing to worry about. We will now take a look at some common mistakes made by students when learning factors. 

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Problem 1

If 155 students are divided equally into groups, what are the possible sizes of the groups?

Okay, lets begin

To determine the possible group sizes, we need the factors of 155:


The factors are 1, 5, 31, and 155. Therefore, the possible group sizes are:


1 student per group: 155 groups
5 students per group: 31 groups
31 students per group: 5 groups
155 students per group: 1 group
 

Explanation

 The possible sizes of the groups are: 1,5,31,155.

Well explained 👍

Problem 2

A teacher has 155 books. If she wants to arrange them into rows of equal size without any remainder, what are the different ways she can arrange the books?

Okay, lets begin

We already know the factors of 155 are 1,5,31 and 155. The teacher can arrange the books in:


1 row of 155 books
5 rows of 31 books
31 rows of 5 books
155 rows of 1 book
 

Explanation

Thus, the different ways she can arrange the books are 1,5,31,155.
 

Well explained 👍

Problem 3

Verify the factor pairs of 155.

Okay, lets begin

List of potential pairs: Consider (x, y) such that x×y=155


Starting with x=1: y=155


Then x=5: y=31


No other integers up to square root of 155 can form pairs that yield 155.


Confirmed pairs: Pairs are (1,155) and (5,31)


Final factor list: Factors are 1,5,31,155
 

Explanation

This is how we verify the factor pairs of the number 155. 
 

Well explained 👍

FAQs on 155 factors

1. What is the factor tree of 155?

We start by dividing 155 with 5 to get 31. It gives 5 and 31. 5 and 31 are prime numbers. Factor tree is a graphical representation of any composite number into combinations of prime numbers.

2. What is the perfect square factorization of 155?

155 as the product of its prime factors is written as, 155= 5×31
We simply break the number into their smaller factors and express the number above. 
 

3. What are the multiples of 155?

The multiples of 155 up to the count of 10 are 155, 310, 465, 620, 930, 1085, 1240, 1395 and 1550.

4.Is 155 a multiple of 11?

Factors of 155 are 1,5,31,155. 11 is not on the list of factors. 155 is not a multiple of 11. Another way to check the same is by dividing the numbers. If a remainder is left, we can conclude it is not divisible by the number.


155/11 = 14.091. 
 

5.What is 155 square root?

Important Glossaries for Factors of 155

  • Factors: Factors are numbers that, when multiplied together, result in a given number.  Example: Factors of 12 are:1 × 12 = 12, 2 × 6 = 12, 3 × 4 = 12. Here, 1, 2, 6, 3, 4 and 12 are the factors of 12.
  • Greatest Common Factor (GCF): The greatest number that divides the given number exactly and is a common factor for the given number is called GCF. An example for GCF is: The GCF of 1500, 10, and 100 is 10. Because it is the greatest factor that is common for all three numbers.
  • Prime number: Any number greater than 1 and has only 2 factors is called a prime number. Example: 811/1 = 811 and 811/811 = 1. We can see that 811 can be divided exactly by only 2 numbers. Those two numbers are 1 and 811.
  • Divisor: Any number that divides another number exactly and leaves no remainder is called a divisor. When we divide 12 by 3, we get a quotient of 4. Here, the divisor is 3 and the dividend is 12.
     

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Hiralee Lalitkumar Makwana

About the Author

Hiralee Lalitkumar Makwana has almost two years of teaching experience. She is a number ninja as she loves numbers. Her interest in numbers can be seen in the way she cracks math puzzles and hidden patterns.

Fun Fact

: She loves to read number jokes and games.