Factor Calculator

Factors of 813

The factors of 813 are 1, 3, 271, and 813. In total, 813 has 4 factors. Its prime factorization is 3 × 271, and the sum of all its factors is 1088.

All factors of 813

Here are all 4 factors of 813, listed from smallest to largest.

13271813

Factor pairs of 813

These 2 pairs of whole numbers each multiply to give 813.

1 × 813 = 813
3 × 271 = 813

Prime factorization of 813

Dividing 813 by the smallest prime at each step gives its prime factorization:

813 ÷ 3 = 271
271 ÷ 271 = 1
Result: 813 = 3 × 271 = 3 × 271

The distinct prime factors of 813 are 3, 271. To factorize any other number, use the prime factorization calculator.

Factor tree of 813

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

Factor tree of 8138133271
Prime factors are shown in solid indigo. Composite numbers split into their smallest prime and the quotient.

Properties of 813

Number of factors4
Sum of factors1088
Sum of proper factors275
Prime factorization3 × 271
Prime or composite?Composite
Even or odd?Odd
Perfect square?No
Perfect cube?No
ClassificationDeficient

What makes 813 interesting

  • 813 is a composite number, meaning it has more than two factors. It can be written as a product of smaller whole numbers in 2 different ways.
  • 813 is a deficient number: its proper factors sum to 275, which is 538 less than 813 itself.

How to find the factors of 813 yourself

Divide 813 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 √81328.51, because every factor above that pairs with one below it.

813 ÷ 1 = 813
813 ÷ 3 = 271

Reading both columns gives every factor: 1, 3, 271, 813. The factor calculator does this automatically for any number.

Frequently asked questions about 813

What are the factors of 813?

The factors of 813 are 1, 3, 271, and 813. That is 4 factors in total, counting both 1 and 813.

Is 813 a prime number?

No, 813 is not prime — it is a composite number with 4 factors. A prime number has exactly two factors, but 813 is also divisible by 3.

What is the prime factorization of 813?

The prime factorization of 813 is 3 × 271. Written out in full: 3 × 271 = 813. Its distinct prime factors are 3, 271.

What two numbers multiply to give 813?

There are 2 pairs of whole numbers that multiply to 813: 1 × 813, 3 × 271.

What is the sum of the factors of 813?

Adding all the factors of 813 together gives 1088. Excluding 813 itself, the proper factors sum to 275.

Is 813 a perfect square?

No, 813 is not a perfect square. There is no whole number that multiplies by itself to give 813. The nearest perfect squares are 784 and 841.

What is the largest factor of 813 other than itself?

The largest factor of 813 apart from 813 itself is 271, since 813 ÷ 271 = 3.

How many factors does 813 have?

813 has 4 factors: 1, 3, 271, and 813. You can verify this from the prime factorization 3 × 271: add 1 to each exponent and multiply, giving 2 × 2 = 4.

Explore more

Try another number in the factor calculator, break 813 down further with the prime factorization calculator, or compare 813 with another number using the GCF calculator and LCM calculator. For divisor counts and sums, see the divisor calculator.