Q: What is the total or count of factors of the number 640?

A: 16

How do I find the total factors of the number 640?

Step 1

Find the prime factorization of the number 640.

Use a factor tree to assist with solving. Take a look at our prime factorization page for additional help.

Factor Tree

	640

2		320

	2		160

		2		80

			2		40

				2		20

					2		10

						2		5

The prime factorization in exponential form is: 2⁷ x 5¹

Step 2

Setup the equation for determining the number of factors or divisors. The equation is:

d(n) = (a + 1)(b + 1)

Where d(n) is equal to the number of divisors of the number and a, b, etc. are equal to the exponents of the prime factorization.

Now substitute the letters in the equation with the the exponents of your prime factorization and then solve to calculate the total number of divisors.

640 = 2⁷ x 5¹

d(n) = (a + 1)(b + 1)

d(640) = (7 + 1)(1 + 1)

d(640) = (8)(2)

d(640) = 16

More numbers for you to try

Take a look at the factors page to see the factors of 640 and how to find them.

Try the factor calculator.

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