How to find the factors of 20
Test every whole number from 1 up to the square root of 20 (√20 ≈ 4.472). Each number that divides evenly gives you two factors at once: the divisor and the quotient.
- 20 ÷ 1 = 20 — so 1 and 20 are factors
- 20 ÷ 2 = 10 — so 2 and 10 are factors
- 20 ÷ 3 = 6.667 — not a whole number
- 20 ÷ 4 = 5 — so 4 and 5 are factors
Collecting both numbers from every successful division gives the complete list: 1, 2, 4, 5, 10 and 20.
Prime factorization of 20
Divide by the smallest prime that fits, and keep going until the quotient is 1:
The primes you divided by give 20 = 2² × 5. From the exponents you can also count the factors without listing them: (2 + 1) × (1 + 1) = 6.
Properties of 20
- 20 is a composite number.
- The sum of all its factors is 42; the sum of its proper factors (excluding 20) is 22, which makes it a abundant number (its proper factors add up to more than itself).
- 20 is not a perfect square, so its factors pair up evenly.
- Multiples of 20 include 40, 60, 80, 100 and so on.
Factors vs. multiples
Factors of 20 are the numbers that divide into it; multiples of 20 are the numbers it divides into. Every number has a limited set of factors but infinitely many multiples. To work with any other number, use the factors calculator, or find shared factors with the GCF calculator.
Frequently asked questions
What are the factors of 20?
The factors of 20 are 1, 2, 4, 5, 10 and 20. Each of these divides 20 with no remainder.
How many factors does 20 have?
20 has 6 positive factors, which form 3 factor pairs. Counting negative factors as well doubles that to 12.
What is the prime factorization of 20?
20 = 2² × 5. Its distinct prime factors are 2 and 5.
Is 20 a prime number?
No. 20 is composite because it has 6 factors, more than the two a prime number has.