Factor Calculator

Factors of 640

The factors of 640 are 1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 128, 160, 320, and 640. In total, 640 has 16 factors. Its prime factorization is 2⁷ × 5, and the sum of all its factors is 1530.

All factors of 640

Here are all 16 factors of 640, listed from smallest to largest.

1245810162032406480128160320640

Factor pairs of 640

These 8 pairs of whole numbers each multiply to give 640.

1 × 640 = 640
2 × 320 = 640
4 × 160 = 640
5 × 128 = 640
8 × 80 = 640
10 × 64 = 640
16 × 40 = 640
20 × 32 = 640

Prime factorization of 640

Dividing 640 by the smallest prime at each step gives its prime factorization:

640 ÷ 2 = 320
320 ÷ 2 = 160
160 ÷ 2 = 80
80 ÷ 2 = 40
40 ÷ 2 = 20
20 ÷ 2 = 10
10 ÷ 2 = 5
5 ÷ 5 = 1
Result: 640 = 2 × 2 × 2 × 2 × 2 × 2 × 2 × 5 = 2⁷ × 5

The distinct prime factors of 640 are 2, 5. To factorize any other number, use the prime factorization calculator.

Factor tree of 640

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

Factor tree of 6406402320216028024022021025
Prime factors are shown in solid indigo. Composite numbers split into their smallest prime and the quotient.

Properties of 640

Number of factors16
Sum of factors1530
Sum of proper factors890
Prime factorization2⁷ × 5
Prime or composite?Composite
Even or odd?Even
Perfect square?No
Perfect cube?No
ClassificationAbundant

What makes 640 interesting

  • 640 is a composite number, meaning it has more than two factors. It can be written as a product of smaller whole numbers in 8 different ways.
  • 640 is an abundant number: its proper factors sum to 890, which is 250 more than 640 itself.

How to find the factors of 640 yourself

Divide 640 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 √640 ≈ 25.30, because every factor above that pairs with one below it.

640 ÷ 1 = 640 ✓
640 ÷ 2 = 320 ✓
640 ÷ 4 = 160 ✓
640 ÷ 5 = 128 ✓
640 ÷ 8 = 80 ✓
640 ÷ 10 = 64 ✓
640 ÷ 16 = 40 ✓
640 ÷ 20 = 32 ✓

Reading both columns gives every factor: 1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 128, 160, 320, 640. The factor calculator does this automatically for any number.

Numbers mathematically connected to 640.

Frequently asked questions about 640

What are the factors of 640?

The factors of 640 are 1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 128, 160, 320, and 640. That is 16 factors in total, counting both 1 and 640.

Is 640 a prime number?

No, 640 is not prime — it is a composite number with 16 factors. A prime number has exactly two factors, but 640 is also divisible by 2.

What is the prime factorization of 640?

The prime factorization of 640 is 2⁷ × 5. Written out in full: 2 × 2 × 2 × 2 × 2 × 2 × 2 × 5 = 640. Its distinct prime factors are 2, 5.

What two numbers multiply to give 640?

There are 8 pairs of whole numbers that multiply to 640: 1 × 640, 2 × 320, 4 × 160, 5 × 128, 8 × 80, 10 × 64, 16 × 40, 20 × 32.

What is the sum of the factors of 640?

Adding all the factors of 640 together gives 1530. Excluding 640 itself, the proper factors sum to 890.

Is 640 a perfect square?

No, 640 is not a perfect square. There is no whole number that multiplies by itself to give 640. The nearest perfect squares are 625 and 676.

What is the largest factor of 640 other than itself?

The largest factor of 640 apart from 640 itself is 320, since 640 ÷ 320 = 2.

How many factors does 640 have?

640 has 16 factors: 1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 128, 160, 320, and 640. You can verify this from the prime factorization 2⁷ × 5: add 1 to each exponent and multiply, giving 8 × 2 = 16.

Explore more

Try another number in the factor calculator, break 640 down further with the prime factorization calculator, or compare 640 with another number using the GCF calculator and LCM calculator. For divisor counts and sums, see the divisor calculator.