Free Maths Calculator

Factors of a Number Calculator

List every factor of a number, hunted in pairs the way it should be done on paper: start at 1, work upwards, and each factor you find hands you its partner for free. The search stops at the square root, which is why the method never misses one and never wastes time.

Try It: Enter Your Numbers

Your question

Updates as you type

Answer

Method, Step by Step

    Worked Example

    List all the factors of 36.

    1. Work upwards from 1 in pairs: 1 × 36, 2 × 18, 3 × 12, 4 × 9, 6 × 6
    2. The pairs have met in the middle at 6, the square root of 36, so stop
    3. In order: 1, 2, 3, 4, 6, 9, 12, 18, 36

    Answer: 1, 2, 3, 4, 6, 9, 12, 18, 36

    Try These Yourself

    List the factors of 12.Show answerHide answer

    Answer: 1, 2, 3, 4, 6, 12

    Pairs: 1 × 12, 2 × 6, 3 × 4.

    How many factors does 13 have?Show answerHide answer

    Answer: Two

    Only 1 and 13, which makes it prime.

    Why does 25 have an odd number of factors?Show answerHide answer

    Answer: It is a square number

    The pair 5 × 5 counts once.