Factor Calculator

Factors of 309

The factors of 309 are 1, 3, 103, and 309. In total, 309 has 4 factors. Its prime factorization is 3 × 103, and the sum of all its factors is 416.

All factors of 309

Here are all 4 factors of 309, listed from smallest to largest.

13103309

Factor pairs of 309

These 2 pairs of whole numbers each multiply to give 309.

1 × 309 = 309
3 × 103 = 309

Prime factorization of 309

Dividing 309 by the smallest prime at each step gives its prime factorization:

309 ÷ 3 = 103
103 ÷ 103 = 1
Result: 309 = 3 × 103 = 3 × 103

The distinct prime factors of 309 are 3, 103. To factorize any other number, use the prime factorization calculator.

Factor tree of 309

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

Factor tree of 3093093103
Prime factors are shown in solid indigo. Composite numbers split into their smallest prime and the quotient.

Properties of 309

Number of factors4
Sum of factors416
Sum of proper factors107
Prime factorization3 × 103
Prime or composite?Composite
Even or odd?Odd
Perfect square?No
Perfect cube?No
ClassificationDeficient

What makes 309 interesting

  • 309 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.
  • 309 is a deficient number: its proper factors sum to 107, which is 202 less than 309 itself.

How to find the factors of 309 yourself

Divide 309 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 √30917.58, because every factor above that pairs with one below it.

309 ÷ 1 = 309
309 ÷ 3 = 103

Reading both columns gives every factor: 1, 3, 103, 309. The factor calculator does this automatically for any number.

Frequently asked questions about 309

What are the factors of 309?

The factors of 309 are 1, 3, 103, and 309. That is 4 factors in total, counting both 1 and 309.

Is 309 a prime number?

No, 309 is not prime — it is a composite number with 4 factors. A prime number has exactly two factors, but 309 is also divisible by 3.

What is the prime factorization of 309?

The prime factorization of 309 is 3 × 103. Written out in full: 3 × 103 = 309. Its distinct prime factors are 3, 103.

What two numbers multiply to give 309?

There are 2 pairs of whole numbers that multiply to 309: 1 × 309, 3 × 103.

What is the sum of the factors of 309?

Adding all the factors of 309 together gives 416. Excluding 309 itself, the proper factors sum to 107.

Is 309 a perfect square?

No, 309 is not a perfect square. There is no whole number that multiplies by itself to give 309. The nearest perfect squares are 289 and 324.

What is the largest factor of 309 other than itself?

The largest factor of 309 apart from 309 itself is 103, since 309 ÷ 103 = 3.

How many factors does 309 have?

309 has 4 factors: 1, 3, 103, and 309. You can verify this from the prime factorization 3 × 103: add 1 to each exponent and multiply, giving 2 × 2 = 4.

Explore more

Try another number in the factor calculator, break 309 down further with the prime factorization calculator, or compare 309 with another number using the GCF calculator and LCM calculator. For divisor counts and sums, see the divisor calculator.