Find every divisor of any number — and know if it's prime
Input
Enter any whole number from 1 to 1,000,000,000.
Try an example
Classification
36 is composite — it has 9 divisors including 1 and itself.
All Factors of 369
Highlighted in red: 1 and 36 (trivial divisors)
Prime Factorization
Stats
How It Works
A factor (or divisor) of n is any integer that divides n with no remainder. This tool finds all factors by trial division up to √n, then tests primality, builds the full prime factorization, and computes divisor sums.
12
Factors: 1, 2, 3, 4, 6, 12
17
Prime — only 1 and 17
28
Perfect: proper divisor sum = 28
The Factors of a Number Calculator instantly lists every factor (divisor) of any positive integer, shows the complete prime factorization with exponents, and determines whether the number is prime, composite, perfect, abundant, or deficient. Whether you are checking homework, studying number theory, or simplifying fractions, this free tool gives you a full divisor breakdown in one click.
A factor (or divisor) of a whole number n is any positive integer that divides n exactly, leaving no remainder. For example, the factors of 12 are 1, 2, 3, 4, 6, and 12.
A prime number has exactly two factors: 1 and itself. If this calculator shows only those two divisors, the number is prime. Examples include 2, 3, 5, 7, 11, and 97.
A perfect number equals the sum of all its proper divisors (divisors excluding itself). The classic example is 28: its proper divisors are 1, 2, 4, 7, and 14, which sum to 28.
Prime factorization expresses a number as a product of prime numbers raised to their respective powers (e.g., 360 = 2³ × 3² × 5). It is fundamental to finding GCDs, LCMs, simplifying fractions, and solving problems in cryptography.