Is 321 a prime number?

Prime Number Checker
Number

Is 321 a prime or composite number?

Answer

Number 321 is not a Prime

321 = 3 × 107

321 has 4 divisors — 1, 3, 107 and 321; a prime has exactly two: 1 and itself.

Primes up to √321

17² = 289 ≤ 321 < 324 = 18², so it is enough to try primes up to 17

  • ÷2 does not divide
  • ÷3 divides

321 ÷ 3 = 107 — 3 divides 321, so 321 is composite

Nearest primes: 317 and 331

Related Calculations

See Also

Prime numbers list

NumberIs Prime
302No: 2 × 151
303No: 3 × 101
304No: 2⁴ × 19
305No: 5 × 61
306No: 2 × 3² × 17
307Yes
309No: 3 × 103
310No: 2 × 5 × 31
311Yes
312No: 2³ × 3 × 13
313Yes
315No: 3² × 5 × 7
317Yes
318No: 2 × 3 × 53
319No: 11 × 29
321No: 3 × 107
322No: 2 × 7 × 23
323No: 17 × 19
324No: 2² × 3⁴
326No: 2 × 163
329No: 7 × 47
331Yes
332No: 2² × 83
333No: 3² × 37
334No: 2 × 167
335No: 5 × 67
336No: 2⁴ × 3 × 7
337Yes
341No: 11 × 31
343No: 7³

FAQ

Is 321 a prime or composite number?

Number 321 is not a Prime

How many factors are in a number 321?

4

How to check if 321 is prime?

Divide 321 by the primes in order: 17² = 289 ≤ 321 < 324 = 18², so it is enough to try primes up to 17. The first one that divides it is 3: 321 ÷ 3 = 107, so 321 is composite.

See Also