Factors of 16

The factors of 16 are 1, 2, 4, 8, and 16. In total, 16 has 5 factors. Its prime factorization is 2⁴, and the sum of all its factors is 31. 16 is also a perfect square, equal to 4 × 4.

All factors of 16

Here are all 5 factors of 16, listed from smallest to largest.

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Factor pairs of 16

These 3 pairs of whole numbers each multiply to give 16.

1 × 16 = 16

2 × 8 = 16

4 × 4 = 16

Notice the pair (4, 4) — because 16 is a perfect square, this pair uses the same number twice.

Prime factorization of 16

Dividing 16 by the smallest prime at each step gives its prime factorization:

16 ÷ 2 = 8

8 ÷ 2 = 4

4 ÷ 2 = 2

2 ÷ 2 = 1

Result: 16 = 2 × 2 × 2 × 2 = 2⁴

The distinct prime factors of 16 are 2. To factorize any other number, use the prime factorization calculator.

Factor tree of 16

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

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

Properties of 16

Number of factors	5
Sum of factors	31
Sum of proper factors	15
Prime factorization	2⁴
Prime or composite?	Composite
Even or odd?	Even
Perfect square?	Yes (4²)
Perfect cube?	No
Classification	Deficient

What makes 16 interesting

16 is a composite number, meaning it has more than two factors. It can be written as a product of smaller whole numbers in 3 different ways.
16 is a perfect square: 4 × 4 = 16. This is why it has an odd number of factors (5) — the pair (4, 4) counts only once.
16 is a deficient number: its proper factors sum to 15, which is 1 less than 16 itself.
16 is a prime power: it is 2 raised to the power of 4. All of its factors are powers of 2.

How to find the factors of 16 yourself

Divide 16 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 √16 ≈ 4.00, because every factor above that pairs with one below it.

16 ÷ 1 = 16 ✓

16 ÷ 2 = 8 ✓

16 ÷ 4 = 4 ✓

Reading both columns gives every factor: 1, 2, 4, 8, 16. The factor calculator does this automatically for any number.

Numbers mathematically connected to 16.

Frequently asked questions about 16

What are the factors of 16?

The factors of 16 are 1, 2, 4, 8, and 16. That is 5 factors in total, counting both 1 and 16.

Is 16 a prime number?

No, 16 is not prime — it is a composite number with 5 factors. A prime number has exactly two factors, but 16 is also divisible by 2.

What is the prime factorization of 16?

The prime factorization of 16 is 2⁴. Written out in full: 2 × 2 × 2 × 2 = 16. Its distinct prime factors are 2.

What two numbers multiply to give 16?

There are 3 pairs of whole numbers that multiply to 16: 1 × 16, 2 × 8, 4 × 4.

What is the sum of the factors of 16?

Adding all the factors of 16 together gives 31. Excluding 16 itself, the proper factors sum to 15.

Is 16 a perfect square?

Yes, 16 is a perfect square. It equals 4 × 4. Perfect squares always have an odd number of factors — 16 has 5.

What is the largest factor of 16 other than itself?

The largest factor of 16 apart from 16 itself is 8, since 16 ÷ 8 = 2.

How many factors does 16 have?

16 has 5 factors: 1, 2, 4, 8, and 16. You can verify this from the prime factorization 2⁴: add 1 to each exponent and multiply, giving 5 = 5.

Explore more

Try another number in the factor calculator, break 16 down further with the prime factorization calculator, or compare 16 with another number using the GCF calculator and LCM calculator. For divisor counts and sums, see the divisor calculator.