Find all common factors (shared divisors) of 2 to 6 numbers — along with the Greatest Common Factor (GCF), factor lists for each number, and step-by-step prime factorization.
Enter Numbers
Greatest Common Factor (GCF)
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GCF
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Common Factors
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LCM
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Co-prime?
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Common Factors
Enter at least 2 numbers above
Common factors are numbers that divide all entered values evenly.
Frequently Asked Questions
How is the GCF found?
The GCF (Greatest Common Factor) is the largest factor shared by all numbers. It can be found by listing all factors and finding the largest common one, or by using the Euclidean algorithm: GCF(a,b) = GCF(b, a mod b).
What does co-prime mean?
Two numbers are co-prime (or relatively prime) when their GCF is 1 — they share no common factors other than 1. For example, 8 and 9 are co-prime even though neither is prime.