Factor Calculator

Factors of 85

The factors of 85 are 1, 5, 17, and 85. In total, 85 has 4 factors. Its prime factorization is 5 × 17, and the sum of all its factors is 108.

All factors of 85

Here are all 4 factors of 85, listed from smallest to largest.

151785

Factor pairs of 85

These 2 pairs of whole numbers each multiply to give 85.

1 × 85 = 85
5 × 17 = 85

Prime factorization of 85

Dividing 85 by the smallest prime at each step gives its prime factorization:

85 ÷ 5 = 17
17 ÷ 17 = 1
Result: 85 = 5 × 17 = 5 × 17

The distinct prime factors of 85 are 5, 17. To factorize any other number, use the prime factorization calculator.

Factor tree of 85

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

Factor tree of 8585517
Prime factors are shown in solid indigo. Composite numbers split into their smallest prime and the quotient.

Properties of 85

Number of factors4
Sum of factors108
Sum of proper factors23
Prime factorization5 × 17
Prime or composite?Composite
Even or odd?Odd
Perfect square?No
Perfect cube?No
ClassificationDeficient

What makes 85 interesting

  • 85 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.
  • 85 is a deficient number: its proper factors sum to 23, which is 62 less than 85 itself.

How to find the factors of 85 yourself

Divide 85 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 √85 ≈ 9.22, because every factor above that pairs with one below it.

85 ÷ 1 = 85 ✓
85 ÷ 5 = 17 ✓

Reading both columns gives every factor: 1, 5, 17, 85. The factor calculator does this automatically for any number.

Numbers mathematically connected to 85.

Frequently asked questions about 85

What are the factors of 85?

The factors of 85 are 1, 5, 17, and 85. That is 4 factors in total, counting both 1 and 85.

Is 85 a prime number?

No, 85 is not prime — it is a composite number with 4 factors. A prime number has exactly two factors, but 85 is also divisible by 5.

What is the prime factorization of 85?

The prime factorization of 85 is 5 × 17. Written out in full: 5 × 17 = 85. Its distinct prime factors are 5, 17.

What two numbers multiply to give 85?

There are 2 pairs of whole numbers that multiply to 85: 1 × 85, 5 × 17.

What is the sum of the factors of 85?

Adding all the factors of 85 together gives 108. Excluding 85 itself, the proper factors sum to 23.

Is 85 a perfect square?

No, 85 is not a perfect square. There is no whole number that multiplies by itself to give 85. The nearest perfect squares are 81 and 100.

What is the largest factor of 85 other than itself?

The largest factor of 85 apart from 85 itself is 17, since 85 ÷ 17 = 5.

How many factors does 85 have?

85 has 4 factors: 1, 5, 17, and 85. You can verify this from the prime factorization 5 × 17: add 1 to each exponent and multiply, giving 2 × 2 = 4.

Explore more

Try another number in the factor calculator, break 85 down further with the prime factorization calculator, or compare 85 with another number using the GCF calculator and LCM calculator. For divisor counts and sums, see the divisor calculator.