Solution: The GCF of 137 and 19 is 1MethodsHow to find the GCF of 137 and 19 using Prime FactorizationOne way to find the GCF of 137 and 19 is to compare the prime factorization of each number. To find the prime factorization, you can follow the instructions for each number here:What are the Factors of 137?What are the Factors of 19?Here is the prime factorization of 137:1371137^11371And this is the prime factorization of 19:19119^1191When you compare the prime factorization of these two numbers, you can see that there are no matching prime factors. When this is the case, it means that there are no common factors between these two numbers. As a result, the GCF of 137 and 19 is 1.Thus, the GCF of 137 and 19 is: 1How to Find the GCF of 137 and 19 by Listing All Common FactorsThe first step to this method of finding the Greatest Common Factor of 137 and 19 is to find and list all the factors of each number. Again, you can see how this is done by looking at the “Factors of” articles that are linked to above.Let’s take a look at the factors for each of these numbers, 137 and 19:Factors of 137: 1, 137Factors of 19: 1, 19When you compare the two lists of factors, you can see that the only common factor is 1. So, in this case, the GCF of 137 and 19 is 1.Find the GCF of Other Number PairsWant more practice? Try some of these other GCF problems:What is the GCF of 39 and 120?What is the GCF of 12 and 143?What is the GCF of 10 and 32?What is the GCF of 104 and 100?What is the GCF of 126 and 103?