Find every factor (divisor) of a number, view factor pairs, check prime or composite status, sum of divisors, perfect number test, divisibility rules, and factor magnitude visualization.
The **Factor Calculator** finds every positive integer that divides a given number with zero remainder. Also called divisors, factors are the building blocks of multiplication and division — understanding them is essential for simplifying fractions, finding GCDs and LCMs, testing primality, and exploring number-theoretic properties like perfect numbers.
Enter any positive integer (up to one billion) and the calculator instantly lists all its factors, organizes them into factor pairs, determines whether the number is prime or composite, and shows its complete prime factorization. It also computes the sum of all divisors (the sigma function σ(n)), the sum of proper divisors (excluding n itself), and checks whether the number is perfect (proper divisor sum = n), abundant, or deficient.
A visual bar chart scales each factor relative to the number itself, making it easy to see the distribution. The divisibility rules view tests the number against rules for 2 through 12 and highlights which ones apply, turning an abstract concept into a concrete reference table. Preset buttons load commonly studied numbers — including 28 and 496, the first two perfect numbers — for instant exploration. Whether you need to check homework, explore number theory, or quickly list divisors for a programming challenge, this calculator gives you every detail at a glance.
A plain list of divisors is useful, but most factor problems require more context than that. This calculator groups factors into pairs, shows the prime factorization, counts how many divisors a number has, and computes the sum of all divisors and proper divisors in one place. That is exactly the combination you need when checking whether a number is prime, simplifying a later GCD problem, or classifying a number as perfect, abundant, or deficient.
The built-in divisibility rules table and factor magnitude bars also make it more practical for teaching and review. Instead of memorizing isolated rules for 3, 4, 8, 9, or 11, you can test a number immediately and compare the visual size of each factor relative to the original value. For students, that makes factor structure easier to see. For programmers and puzzle-solvers, it speeds up validation before moving on to prime factorization, LCM, or modular arithmetic work.
d is a factor of n if n mod d = 0. Number of divisors: τ(n) = ∏(eᵢ + 1) from prime factorization n = ∏ pᵢ^eᵢ. Sum of divisors: σ(n) = ∏ (pᵢ^(eᵢ+1) − 1)/(pᵢ − 1).
Result: For these inputs, the calculator returns the factor calculator — find all factors of a number result plus supporting breakdown values shown in the output cards.
This example reflects the built-in factor calculator — find all factors of a number workflow: enter values, apply options, and read both the main answer and supporting metrics.
Listing factors is only the starting point. The factor pairs table shows how a number can be built multiplicatively, which is helpful when solving rectangle-area problems, simplifying radicals, or spotting whether a number is a square. The prime factorization output then compresses that same structure into a form you can reuse for GCD, GCF, LCM, and divisor-count formulas.
The calculator also reports the sum of proper divisors, which lets you classify numbers in a more interesting way. If the proper divisors add up exactly to the number, it is perfect, like 28. If they add to more than the number, it is abundant. If they add to less, it is deficient. Those labels appear often in contest math and number theory, and the preset values make them easy to explore.
For many arithmetic tasks, you do not need full factorization right away. Sometimes you just need to know whether a number is divisible by 6, 8, 9, or 12 before simplifying a fraction or checking if a computation is valid. The divisibility view gives a fast screening step, while the full factor list confirms the exact divisors when you need a complete answer.
Factors are integers that divide a number evenly with no remainder. For 12, the factors are 1, 2, 3, 4, 6, and 12.
Test each integer from 1 to √n. If n/i has no remainder, both i and n/i are factors. For 36: test 1-6, finding pairs (1,36), (2,18), (3,12), (4,9), (6,6).
Factors divide into a number (12 has factors 1,2,3,4,6,12). Multiples are products of a number (multiples of 12 are 12,24,36,...). Factors are finite; multiples are infinite.
A factor divides a number evenly, while a multiple is produced by multiplying a number by an integer. For example, 4 is a factor of 12, and 12 is a multiple of 4.
A prime number has exactly two factors: 1 and itself. This is the defining property of primes and distinguishes them from composite numbers.
Factor pairs are sets of two numbers whose product equals the original number. For 24, the factor pairs are (1,24), (2,12), (3,8), and (4,6). Every factor can be paired with another factor this way.