Factor Calculator

Factors of 105

The factors of 105 are 1, 3, 5, 7, 15, 21, 35, and 105. In total, 105 has 8 factors. Its prime factorization is 3 × 5 × 7, and the sum of all its factors is 192.

All factors of 105

Here are all 8 factors of 105, listed from smallest to largest.

1357152135105

Factor pairs of 105

These 4 pairs of whole numbers each multiply to give 105.

1 × 105 = 105
3 × 35 = 105
5 × 21 = 105
7 × 15 = 105

Prime factorization of 105

Dividing 105 by the smallest prime at each step gives its prime factorization:

105 ÷ 3 = 35
35 ÷ 5 = 7
7 ÷ 7 = 1
Result: 105 = 3 × 5 × 7 = 3 × 5 × 7

The distinct prime factors of 105 are 3, 5, 7. To factorize any other number, use the prime factorization calculator.

Factor tree of 105

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

Factor tree of 10510533557
Prime factors are shown in solid indigo. Composite numbers split into their smallest prime and the quotient.

Properties of 105

Number of factors8
Sum of factors192
Sum of proper factors87
Prime factorization3 × 5 × 7
Prime or composite?Composite
Even or odd?Odd
Perfect square?No
Perfect cube?No
ClassificationDeficient

What makes 105 interesting

  • 105 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.
  • 105 is a deficient number: its proper factors sum to 87, which is 18 less than 105 itself.
  • 105 is a triangular number — it is the sum of the first 14 whole numbers (1 + 2 + … + 14 = 105).
  • 105 has 3 distinct prime factors (3, 5, 7), which is why it has so many divisors.

How to find the factors of 105 yourself

Divide 105 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 √10510.25, because every factor above that pairs with one below it.

105 ÷ 1 = 105
105 ÷ 3 = 35
105 ÷ 5 = 21
105 ÷ 7 = 15

Reading both columns gives every factor: 1, 3, 5, 7, 15, 21, 35, 105. The factor calculator does this automatically for any number.

Frequently asked questions about 105

What are the factors of 105?

The factors of 105 are 1, 3, 5, 7, 15, 21, 35, and 105. That is 8 factors in total, counting both 1 and 105.

Is 105 a prime number?

No, 105 is not prime — it is a composite number with 8 factors. A prime number has exactly two factors, but 105 is also divisible by 3.

What is the prime factorization of 105?

The prime factorization of 105 is 3 × 5 × 7. Written out in full: 3 × 5 × 7 = 105. Its distinct prime factors are 3, 5, 7.

What two numbers multiply to give 105?

There are 4 pairs of whole numbers that multiply to 105: 1 × 105, 3 × 35, 5 × 21, 7 × 15.

What is the sum of the factors of 105?

Adding all the factors of 105 together gives 192. Excluding 105 itself, the proper factors sum to 87.

Is 105 a perfect square?

No, 105 is not a perfect square. There is no whole number that multiplies by itself to give 105. The nearest perfect squares are 100 and 121.

What is the largest factor of 105 other than itself?

The largest factor of 105 apart from 105 itself is 35, since 105 ÷ 35 = 3.

How many factors does 105 have?

105 has 8 factors: 1, 3, 5, 7, 15, 21, 35, and 105. You can verify this from the prime factorization 3 × 5 × 7: add 1 to each exponent and multiply, giving 2 × 2 × 2 = 8.

Explore more

Try another number in the factor calculator, break 105 down further with the prime factorization calculator, or compare 105 with another number using the GCF calculator and LCM calculator. For divisor counts and sums, see the divisor calculator.