Factors of 128

How to find the factors of 128

Test every whole number from 1 up to the square root of 128 (√128 ≈ 11.314). Each number that divides evenly gives you two factors at once: the divisor and the quotient.

• 128 ÷ 1 = 128 — so 1 and 128 are factors
• 128 ÷ 2 = 64 — so 2 and 64 are factors
• 128 ÷ 3 = 42.667 — not a whole number
• 128 ÷ 4 = 32 — so 4 and 32 are factors
• 128 ÷ 5 = 25.6 — not a whole number
• 128 ÷ 6 = 21.333 — not a whole number
• 128 ÷ 7 = 18.286 — not a whole number
• 128 ÷ 8 = 16 — so 8 and 16 are factors
• 128 ÷ 9 = 14.222 — not a whole number
• 128 ÷ 10 = 12.8 — not a whole number
• 128 ÷ 11 = 11.636 — not a whole number

Collecting both numbers from every successful division gives the complete list: 1, 2, 4, 8, 16, 32, 64 and 128.

Prime factorization of 128

Divide by the smallest prime that fits, and keep going until the quotient is 1:

The primes you divided by give 128 = 2⁷. From the exponents you can also count the factors without listing them: (7 + 1) = 8.

Properties of 128

• 128 is a composite number.
• The sum of all its factors is 255; the sum of its proper factors (excluding 128) is 127, which makes it a deficient number (its proper factors add up to less than itself).
• 128 is not a perfect square, so its factors pair up evenly.
• Multiples of 128 include 256, 384, 512, 640 and so on.

Factors vs. multiples

Factors of 128 are the numbers that divide into it; multiples of 128 are the numbers it divides into. Every number has a limited set of factors but infinitely many multiples. To work with any other number, use the factors calculator, or find shared factors with the GCF calculator.