Is 231 a prime number?

Prime Number Checker
Number

Is 231 a prime or composite number?

Answer

Number 231 is not a Prime

231 = 3 × 7 × 11

231 has 8 divisors — 1, 3, 7, 11, 21, 33, 77 and 231; a prime has exactly two: 1 and itself.

Primes up to √231

15² = 225 ≤ 231 < 256 = 16², so it is enough to try primes up to 15

  • ÷2 does not divide
  • ÷3 divides

231 ÷ 3 = 77 — 3 divides 231, so 231 is composite

Nearest primes: 229 and 233

Related Calculations

See Also

Prime numbers list

NumberIs Prime
211Yes
213No: 3 × 71
214No: 2 × 107
215No: 5 × 43
216No: 2³ × 3³
217No: 7 × 31
219No: 3 × 73
220No: 2² × 5 × 11
221No: 13 × 17
222No: 2 × 3 × 37
223Yes
225No: 3² × 5²
226No: 2 × 113
227Yes
229Yes
231No: 3 × 7 × 11
232No: 2³ × 29
233Yes
234No: 2 × 3² × 13
235No: 5 × 47
237No: 3 × 79
238No: 2 × 7 × 17
239Yes
240No: 2⁴ × 3 × 5
241Yes
243No: 3⁵
246No: 2 × 3 × 41
247No: 13 × 19
249No: 3 × 83
250No: 2 × 5³

FAQ

Is 231 a prime or composite number?

Number 231 is not a Prime

How many factors are in a number 231?

8

How to check if 231 is prime?

Divide 231 by the primes in order: 15² = 225 ≤ 231 < 256 = 16², so it is enough to try primes up to 15. The first one that divides it is 3: 231 ÷ 3 = 77, so 231 is composite.

See Also