Is 721 a prime number?

Prime Number Checker
Number

Is 721 a prime or composite number?

Answer

Number 721 is not a Prime

721 = 7 × 103

721 has 4 divisors — 1, 7, 103 and 721; a prime has exactly two: 1 and itself.

Primes up to √721

26² = 676 ≤ 721 < 729 = 27², so it is enough to try primes up to 26

  • ÷2 does not divide
  • ÷3 does not divide
  • ÷5 does not divide
  • ÷7 divides

721 ÷ 7 = 103 — 7 divides 721, so 721 is composite

Nearest primes: 719 and 727

Related Calculations

See Also

Prime numbers list

NumberIs Prime
693No: 3² × 7 × 11
694No: 2 × 347
697No: 17 × 41
698No: 2 × 349
699No: 3 × 233
701Yes
702No: 2 × 3³ × 13
703No: 19 × 37
705No: 3 × 5 × 47
707No: 7 × 101
709Yes
711No: 3² × 79
713No: 23 × 31
716No: 2² × 179
719Yes
721No: 7 × 103
723No: 3 × 241
724No: 2² × 181
727Yes
729No: 3⁶
731No: 17 × 43
732No: 2² × 3 × 61
733Yes
736No: 2⁵ × 23
737No: 11 × 67
738No: 2 × 3² × 41
739Yes
741No: 3 × 13 × 19
742No: 2 × 7 × 53
743Yes

FAQ

Is 721 a prime or composite number?

Number 721 is not a Prime

How many factors are in a number 721?

4

How to check if 721 is prime?

Divide 721 by the primes in order: 26² = 676 ≤ 721 < 729 = 27², so it is enough to try primes up to 26. The first one that divides it is 7: 721 ÷ 7 = 103, so 721 is composite.

See Also