What Are the Factors of 180?
A straight angle is 180 degrees and the three angles of any triangle add up to 180, so this number is everywhere in geometry. Every one of those tidy splits is a factor: a whole number that divides another number exactly, with no remainder.
The factors of 180 are 1, 2, 3, 4, 5, 6, 9, 10, 12, 15, 18, 20, 30, 36, 45, 60, 90 and 180. That is eighteen factors.
Factor Pairs of 180
Look for pairs that multiply to 180, working from the outside in.

- Start with 1 × 180.
- Try 2. Since 180 ÷ 2 = 90, write 2 × 90.
- Try 3. Since 180 ÷ 3 = 60, write 3 × 60.
- Try 4. Since 180 ÷ 4 = 45, write 4 × 45.
- Try 5. Since 180 ÷ 5 = 36, write 5 × 36.
- Try 6. Since 180 ÷ 6 = 30, write 6 × 30.
- Try 9. Since 180 ÷ 9 = 20, write 9 × 20.
- Try 10. Since 180 ÷ 10 = 18, write 10 × 18.
- Try 12. Since 180 ÷ 12 = 15, write 12 × 15.
- Keep trying whole numbers until you reach 15, which is already in your list. Every factor is now found, so you are done.
Prime Factorization of 180
Prime factors show what 180 is built from. Split it and keep going until every branch is a prime.

So 180 = 2 × 2 × 3 × 3 × 5 = 2² × 3² × 5. Its prime factors are 2, 3 and 5. Add 1 to each exponent and multiply: (2 + 1) × (2 + 1) × (1 + 1) = 18, which matches the list.
Divisibility check for 180
A number divides by 180 when it divides by 4, 9 and 5. Take 540: its last two digits give 40 ÷ 4 = 10, its digits add up to 9, and it ends in 0, so 540 is a multiple of 180.
Is 180 a Prime or Composite Number?
Composite. It has eighteen factors. The sum of all factors is 1 + 2 + 3 + 4 + 5 + 6 + 9 + 10 + 12 + 15 + 18 + 20 + 30 + 36 + 45 + 60 + 90 + 180 = 546. The factors smaller than 180 add up to 366, which is more than 180, so 180 is called an abundant number.
Real-Life Uses of the Factors of 180
- Triangles. The three angles of any triangle add up to 180 degrees.
- Straight lines. A straight angle measures 180 degrees.
- Groups. With eighteen factors, 180 students can form equal groups of 2, 3, 4, 5, 6, 9, 10, 12 and more with nobody left out.
Common Factors of 180 With Other Numbers
The factors of 240 are 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 20, 24, 30, 40, 48, 60, 80, 120 and 240, so 180 and 240 share 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30 and 60. The GCF is 60, which simplifies 180/240 to 3/4.
Quick Practice
Which of these are factors of 180: 7, 5 or 11? Only 5. Now try 18 and check it with the calculator.