Factor Calculator

Factors of 40

The factors of 40 are 1, 2, 4, 5, 8, 10, 20, and 40. In total, 40 has 8 factors. Its prime factorization is 2³ × 5, and the sum of all its factors is 90.

All factors of 40

Here are all 8 factors of 40, listed from smallest to largest.

12458102040

Factor pairs of 40

These 4 pairs of whole numbers each multiply to give 40.

1 × 40 = 40
2 × 20 = 40
4 × 10 = 40
5 × 8 = 40

Prime factorization of 40

Dividing 40 by the smallest prime at each step gives its prime factorization:

40 ÷ 2 = 20
20 ÷ 2 = 10
10 ÷ 2 = 5
5 ÷ 5 = 1
Result: 40 = 2 × 2 × 2 × 5 = 2³ × 5

The distinct prime factors of 40 are 2, 5. To factorize any other number, use the prime factorization calculator.

Factor tree of 40

A factor tree shows the same prime factorization visually. Each composite branch splits until every endpoint is a prime number.

Factor tree of 404022021025
Prime factors are shown in solid indigo. Composite numbers split into their smallest prime and the quotient.

Properties of 40

Number of factors8
Sum of factors90
Sum of proper factors50
Prime factorization2³ × 5
Prime or composite?Composite
Even or odd?Even
Perfect square?No
Perfect cube?No
ClassificationAbundant

What makes 40 interesting

  • 40 is a composite number, meaning it has more than two factors. It can be written as a product of smaller whole numbers in 4 different ways.
  • 40 is an abundant number: its proper factors sum to 50, which is 10 more than 40 itself.

How to find the factors of 40 yourself

Divide 40 by each whole number starting from 1. Whenever the division leaves no remainder, both the divisor and the quotient are factors. You only need to test up to √40 ≈ 6.32, because every factor above that pairs with one below it.

40 ÷ 1 = 40 ✓
40 ÷ 2 = 20 ✓
40 ÷ 4 = 10 ✓
40 ÷ 5 = 8 ✓

Reading both columns gives every factor: 1, 2, 4, 5, 8, 10, 20, 40. The factor calculator does this automatically for any number.

Numbers mathematically connected to 40.

Frequently asked questions about 40

What are the factors of 40?

The factors of 40 are 1, 2, 4, 5, 8, 10, 20, and 40. That is 8 factors in total, counting both 1 and 40.

Is 40 a prime number?

No, 40 is not prime — it is a composite number with 8 factors. A prime number has exactly two factors, but 40 is also divisible by 2.

What is the prime factorization of 40?

The prime factorization of 40 is 2³ × 5. Written out in full: 2 × 2 × 2 × 5 = 40. Its distinct prime factors are 2, 5.

What two numbers multiply to give 40?

There are 4 pairs of whole numbers that multiply to 40: 1 × 40, 2 × 20, 4 × 10, 5 × 8.

What is the sum of the factors of 40?

Adding all the factors of 40 together gives 90. Excluding 40 itself, the proper factors sum to 50.

Is 40 a perfect square?

No, 40 is not a perfect square. There is no whole number that multiplies by itself to give 40. The nearest perfect squares are 36 and 49.

What is the largest factor of 40 other than itself?

The largest factor of 40 apart from 40 itself is 20, since 40 ÷ 20 = 2.

How many factors does 40 have?

40 has 8 factors: 1, 2, 4, 5, 8, 10, 20, and 40. You can verify this from the prime factorization 2³ × 5: add 1 to each exponent and multiply, giving 4 × 2 = 8.

Explore more

Try another number in the factor calculator, break 40 down further with the prime factorization calculator, or compare 40 with another number using the GCF calculator and LCM calculator. For divisor counts and sums, see the divisor calculator.