Factors of 721

How to find the factors of 721

Test every whole number from 1 up to the square root of 721 (√721 ≈ 26.851). Each number that divides evenly gives you two factors at once: the divisor and the quotient.

• 721 ÷ 1 = 721 — so 1 and 721 are factors
• 721 ÷ 2 = 360.5 — not a whole number
• 721 ÷ 3 = 240.333 — not a whole number
• 721 ÷ 4 = 180.25 — not a whole number
• 721 ÷ 5 = 144.2 — not a whole number
• 721 ÷ 6 = 120.167 — not a whole number
• 721 ÷ 7 = 103 — so 7 and 103 are factors
• 721 ÷ 8 = 90.125 — not a whole number
• 721 ÷ 9 = 80.111 — not a whole number
• 721 ÷ 10 = 72.1 — not a whole number
• 721 ÷ 11 = 65.545 — not a whole number
• 721 ÷ 12 = 60.083 — not a whole number
• 721 ÷ 13 = 55.462 — not a whole number
• 721 ÷ 14 = 51.5 — not a whole number
• 721 ÷ 15 = 48.067 — not a whole number
• 721 ÷ 16 = 45.063 — not a whole number
• 721 ÷ 17 = 42.412 — not a whole number
• 721 ÷ 18 = 40.056 — not a whole number
• 721 ÷ 19 = 37.947 — not a whole number
• 721 ÷ 20 = 36.05 — not a whole number
• 721 ÷ 21 = 34.333 — not a whole number
• 721 ÷ 22 = 32.773 — not a whole number
• 721 ÷ 23 = 31.348 — not a whole number
• 721 ÷ 24 = 30.042 — not a whole number
• 721 ÷ 25 = 28.84 — not a whole number
• 721 ÷ 26 = 27.731 — not a whole number

Collecting both numbers from every successful division gives the complete list: 1, 7, 103 and 721.

Prime factorization of 721

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

The primes you divided by give 721 = 7 × 103. From the exponents you can also count the factors without listing them: (1 + 1) × (1 + 1) = 4.

Properties of 721

• 721 is a composite number.
• The sum of all its factors is 832; the sum of its proper factors (excluding 721) is 111, which makes it a deficient number (its proper factors add up to less than itself).
• 721 is not a perfect square, so its factors pair up evenly.
• Multiples of 721 include 1,442, 2,163, 2,884, 3,605 and so on.

Factors vs. multiples

Factors of 721 are the numbers that divide into it; multiples of 721 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.