Factors of 255

How to find the factors of 255

Test every whole number from 1 up to the square root of 255 (√255 ≈ 15.969). Each number that divides evenly gives you two factors at once: the divisor and the quotient.

• 255 ÷ 1 = 255 — so 1 and 255 are factors
• 255 ÷ 2 = 127.5 — not a whole number
• 255 ÷ 3 = 85 — so 3 and 85 are factors
• 255 ÷ 4 = 63.75 — not a whole number
• 255 ÷ 5 = 51 — so 5 and 51 are factors
• 255 ÷ 6 = 42.5 — not a whole number
• 255 ÷ 7 = 36.429 — not a whole number
• 255 ÷ 8 = 31.875 — not a whole number
• 255 ÷ 9 = 28.333 — not a whole number
• 255 ÷ 10 = 25.5 — not a whole number
• 255 ÷ 11 = 23.182 — not a whole number
• 255 ÷ 12 = 21.25 — not a whole number
• 255 ÷ 13 = 19.615 — not a whole number
• 255 ÷ 14 = 18.214 — not a whole number
• 255 ÷ 15 = 17 — so 15 and 17 are factors

Collecting both numbers from every successful division gives the complete list: 1, 3, 5, 15, 17, 51, 85 and 255.

Prime factorization of 255

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

The primes you divided by give 255 = 3 × 5 × 17. From the exponents you can also count the factors without listing them: (1 + 1) × (1 + 1) × (1 + 1) = 8.

Properties of 255

• 255 is a composite number.
• The sum of all its factors is 432; the sum of its proper factors (excluding 255) is 177, which makes it a deficient number (its proper factors add up to less than itself).
• 255 is not a perfect square, so its factors pair up evenly.
• Multiples of 255 include 510, 765, 1,020, 1,275 and so on.

Factors vs. multiples

Factors of 255 are the numbers that divide into it; multiples of 255 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.