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List all factors of a number.
A factor calculator lists every factor (divisor) of a whole number and gives its prime factorization — the unique set of prime numbers that multiply together to make it.
Factors and prime factorization underpin simplifying fractions, finding common denominators, computing GCF and LCM, and much of number theory.
By the fundamental theorem of arithmetic, every whole number greater than 1 has exactly one prime factorization.
A factor is any whole number that divides evenly. A prime factor is a factor that is itself prime. For 12 the factors are 1, 2, 3, 4, 6, 12 while the prime factors are just 2 and 3.
Prime factorization reveals the common factors of the numerator and denominator, letting you cancel them to reduce the fraction to lowest terms.
Very large numbers require far more computation to factor. Capping the input keeps results instant in the browser.