Factors of 40
There are 8 factors of 40 — the full list is below, with factor pairs, prime factorization, and divisibility notes.
Factors of 40
1, 2, 4, 5, 8, 10, 20, 40
Factor pairs of 40
- 1 × 40
- 2 × 20
- 4 × 10
- 5 × 8
Prime factorization of 40
40 = 2³ × 5
Number facts
- 40 is a composite number.
- 40 has 8 factors.
- 40 is not a perfect square.
- The sum of all factors of 40 is 90.
Divisibility rules that apply to 40
- 40 is divisible by 2 because it ends in an even digit (0, 2, 4, 6, or 8).
- 40 is divisible by 5 because it ends in 0 or 5.
- 40 is divisible by 10 because it ends in 0.
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How the factors of 40 are calculated
To find the factors of 40, every whole number from 1 up to the square root of 40(about 6.32) is tested for even division. 40 is even, and it divides evenly by 2, 4, 5, 8, among others. Written as a product of primes, 40 = 2³ × 5, which confirms every factor above is a combination of those prime building blocks.
Frequently asked questions about 40
How many factors does 40 have?
40 has 8 factors: 1, 2, 4, 5, 8, 10, 20, 40.
Is 40 a prime number?
No. 40 is composite because it has factors other than 1 and itself.
What are the factor pairs of 40?
The factor pairs of 40 are 1 × 40, 2 × 20, 4 × 10, 5 × 8.
What is the prime factorization of 40?
The prime factorization of 40 is 2³ × 5.