GCF for 42 and 231

What is the Greatest common Divisor of 42 and 231?

Answer: GCF of 42 and 231 is 21

(Twenty-one)

Finding GCF for 42 and 231 using all factors (divisors) listing

The first method to find GCF for numbers 42 and 231 is to list all factors for both numbers and pick the highest common one:

All factors of 42: 1, 2, 3, 6, 7, 14, 21, 42

All factors of 231: 1, 3, 7, 11, 21, 33, 77, 231

So the Greatest Common Factor for 42 and 231 is 21

Finding GCF for 42 and 231 by Prime Factorization

The second method to find GCF for numbers 42 and 231 is to list all Prime Factors for both numbers and multiply the common ones:

All Prime Factors of 42: 2, 3, 7

All Prime Factors of 231: 3, 7, 11

As we can see there are Prime Factors common to both numbers: 3, 7

Now we need to multiply them to find GCF: 3 × 7 = 21

Related Calculations

See Also

About "Greatest Common Factor" Calculator

This calculator will help you find the greatest common factor (GCF) of two numbers. For example, it can help you find out what is the Greatest common Divisor of 42 and 231? (The answer is: 21). Select the first number (e.g. '42') and the second number (e.g. '231'). After that hit the 'Calculate' button.
Greatest Common Factor (GCF) also known as the Greatest Common Divisor (GCD) or Highest Common Factor (HCF) - it is the largest positive integer that divides each of the integers with zero remainder

GCF Table

Number 1Number 2GCF
272313
282317
292311
302313
312311
322311
3323133
342311
352317
362313
372311
382311
392313
402311
412311
42231
432311
4423111
452313
462311
472311
482313
492317
502311
512313
522311
532311
542313
5523111
562317

FAQ

What is the Greatest common Divisor of 42 and 231?

GCF of 42 and 231 is 21