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 105 Learners
105 LearnersLast updated on October 29, 2025

The numbers that two or more other numbers share as factors are called common factors. This article discusses the common factors of 17 and 51. We’ll also learn how to use the concept of common factors in our everyday life.
The common factor of 17 and 51 is 1. There are different methods to find the common factors of two or more numbers. Let’s focus on the listing factors method.
Let’s use the listing factors method here. The first step is to list all the factors of 17 and 51 separately. Once the factors of both numbers are listed, we can compare them and identify the common factors.
Step 1: List all the factors
Factors of 17: 1, 17
Factors of 51: 1, 3, 17, 51
Step 2: Compare and identify common factors 1 is the number that appears in both lists of factors.
Therefore, it is the only common factor of 17 and 51.
As mentioned earlier, there are different methods to find the common factors. We’ve already seen the listing factors method, and this section discusses the other commonly used methods.
Prime Factorization: For large numbers, finding the common factors using the listing factors method is quite laborious. Hence, we use the prime factorization method, where we find the prime factorization of each number to identify the common prime factors. Since 17 is prime, it only has itself and 1 as factors. The prime factors of 51 are 3 and 17. Therefore, 1 is the only common factor.
Venn Diagram: Students who are good at visualization are encouraged to use this method, as it combines prime factorization and visual thinking. The first step is to prime factor each number and place the factors in a Venn diagram. The overlapping section shows the shared primes; multiply them to get the GCF. Here, the only common factor is 1.
Division Ladder Method: The first step is to find all the prime numbers that can divide the given numbers without leaving any remainder. Once we have all the prime numbers, multiply them to get the GCF. Since the numbers in this case are relatively small, the common factor is simply 1.
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.
: She loves to read number jokes and games.

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