Factors of 243

How to find the factors of 243

Test every whole number from 1 up to the square root of 243 (√243 ≈ 15.588). Each number that divides evenly gives you two factors at once: the divisor and the quotient.

• 243 ÷ 1 = 243 — so 1 and 243 are factors
• 243 ÷ 2 = 121.5 — not a whole number
• 243 ÷ 3 = 81 — so 3 and 81 are factors
• 243 ÷ 4 = 60.75 — not a whole number
• 243 ÷ 5 = 48.6 — not a whole number
• 243 ÷ 6 = 40.5 — not a whole number
• 243 ÷ 7 = 34.714 — not a whole number
• 243 ÷ 8 = 30.375 — not a whole number
• 243 ÷ 9 = 27 — so 9 and 27 are factors
• 243 ÷ 10 = 24.3 — not a whole number
• 243 ÷ 11 = 22.091 — not a whole number
• 243 ÷ 12 = 20.25 — not a whole number
• 243 ÷ 13 = 18.692 — not a whole number
• 243 ÷ 14 = 17.357 — not a whole number
• 243 ÷ 15 = 16.2 — not a whole number

Collecting both numbers from every successful division gives the complete list: 1, 3, 9, 27, 81 and 243.

Prime factorization of 243

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

The primes you divided by give 243 = 3⁵. From the exponents you can also count the factors without listing them: (5 + 1) = 6.

Properties of 243

• 243 is a composite number.
• The sum of all its factors is 364; the sum of its proper factors (excluding 243) is 121, which makes it a deficient number (its proper factors add up to less than itself).
• 243 is not a perfect square, so its factors pair up evenly.
• Multiples of 243 include 486, 729, 972, 1,215 and so on.

Factors vs. multiples

Factors of 243 are the numbers that divide into it; multiples of 243 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.