Factor Calculator

Find every positive factor, factor pair, and prime factorization of an integer.

Find all factors
Enter a positive integer from 1 to 10,000,000.

About factors and divisors

A factor of a positive integer is another positive integer that divides it with no remainder. For example, 3 is a factor of 12 because 12 divided by 3 is exactly 4. The complete positive factor list of 12 is 1, 2, 3, 4, 6, and 12. The words factor and divisor are commonly used interchangeably in elementary number theory. Factors naturally occur in pairs. If d divides n, then n divided by d is also a factor, so multiplying the pair recreates n. For 24, the pairs are 1 times 24, 2 times 12, 3 times 8, and 4 times 6. The calculator tests candidates only through the square root of the number and adds both members of each successful pair. This is faster than checking every integer up to n and guarantees the sorted list is complete. Prime factorization expresses an integer as a product of prime numbers. The number 24 becomes 2^3 times 3 because it contains three factors of 2 and one factor of 3. Apart from the order of those primes, every integer greater than 1 has one unique prime factorization. That fundamental theorem of arithmetic makes prime factors useful for simplifying fractions, calculating greatest common factors and least common multiples, and studying divisibility. A perfect square has an odd number of positive factors because its square-root pair contains the same number twice. For example, 36 has the central pair 6 times 6, so 6 appears only once in the factor list. Every nonsquare has an even number of factors. The number 1 is a special case: it has one factor, itself, and it is neither prime nor composite. Factors support many practical tasks. They identify possible rectangular dimensions for a fixed area, help divide objects into equal groups, determine repeating schedules, and reveal useful number patterns. In algebra, factoring reverses multiplication and helps simplify expressions or solve equations. In cryptography, the difficulty of factoring very large products of primes helps protect information. This calculator is intended for exact positive-integer exploration within its stated range, and it presents the full divisor list, paired products, factor count, and prime structure together.

Factor calculator examples

These examples include a prime, a perfect number, and a perfect square.

NumberFactorsNumber property
61, 2, 3, 6The smallest perfect number.
131, 13A prime number has exactly two positive factors.
361, 2, 3, 4, 6, 9, 12, 18, 36A perfect square with nine factors.
1201, 2, 3, 4, 5, 6, 8, 10, 12, 15, 20, 24, 30, 40, 60, 120A highly composite three-digit number.

How to use the factor calculator

  1. Enter one positive whole number from 1 to 10,000,000.
  2. Select Calculate Factors to test divisors through the number's square root.
  3. Read the sorted factor list and count.
  4. Review the prime factorization and paired products to understand the number's structure.

Factor calculator FAQ

What is the difference between a factor and a multiple?

A factor divides a number exactly, while a multiple is produced by multiplying that number by an integer. For example, 3 is a factor of 12, while 24 is a multiple of 12.

Is 1 a factor of every positive integer?

Yes, dividing any positive integer by 1 leaves no remainder. The number itself is also always included in its positive factor list.

Is 1 a prime number?

No, 1 is neither prime nor composite. A prime must have exactly two distinct positive factors, but 1 has only one.

Why do perfect squares have an odd number of factors?

Most factors pair with a different quotient. In a perfect square, the square root pairs with itself and is counted once, leaving an odd total.

How is the number of factors found from prime factorization?

Add one to every exponent in the prime factorization and multiply those values. For 60 = 2^2 times 3 times 5, the count is 3 times 2 times 2, or 12.