Factors of 28
There are 6 factors of 28 — the full list is below, with factor pairs, prime factorization, and divisibility notes.
Factors of 28
1, 2, 4, 7, 14, 28
Factor pairs of 28
- 1 × 28
- 2 × 14
- 4 × 7
Prime factorization of 28
28 = 2² × 7
Number facts
- 28 is a composite number.
- 28 has 6 factors.
- 28 is not a perfect square.
- The sum of all factors of 28 is 56.
Divisibility rules that apply to 28
- 28 is divisible by 2 because it ends in an even digit (0, 2, 4, 6, or 8).
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How the factors of 28 are calculated
To find the factors of 28, every whole number from 1 up to the square root of 28(about 5.29) is tested for even division. 28 is even, and it divides evenly by 2, 4, 7, 14. Written as a product of primes, 28 = 2² × 7, which confirms every factor above is a combination of those prime building blocks.
Frequently asked questions about 28
How many factors does 28 have?
28 has 6 factors: 1, 2, 4, 7, 14, 28.
Is 28 a prime number?
No. 28 is composite because it has factors other than 1 and itself.
What are the factor pairs of 28?
The factor pairs of 28 are 1 × 28, 2 × 14, 4 × 7.
What is the prime factorization of 28?
The prime factorization of 28 is 2² × 7.