Factor Calculator
List all factors of a number, its factor pairs and prime factorization — and check whether it is prime.
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What are factors?
Factors (divisors) of a number divide it with no remainder. The factors of 72 are 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36 and 72 — twelve in total — and they come in pairs: 1 × 72, 2 × 36, 3 × 24, 4 × 18, 6 × 12, 8 × 9.
Counting factors from the prime factorization
72 = 2³ × 3². Add 1 to each exponent and multiply: (3 + 1) × (2 + 1) = 12 factors.
Prime numbers
A number with exactly two factors, 1 and itself, is prime. The calculator checks numbers up to one trillion.
Frequently asked questions
What are the factors of 72?
1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36 and 72.
How do I check if a number is prime?
Enter it — if its only factors are 1 and the number itself, it is prime.