Is 643 is a prime number or not ?
- As we already know that, the number having factors 1 and the number itself is the prime number.
- And numbers having more than these two factors are the composite numbers.
- To check whether the number 643 is prime or not first we have to find its factors.
Contents
Factors of 643:
- If we have taken numbers from 1, 2, 3…for checking factors of 643, we found that 643 has factors 1 and the number 643 itself. Hence, we must say that 643 is a prime number.
- Thus, 643 is the prime number.
- Here, 643 is the odd prime number.
- If we multiply 643 by 1, 2, 3, then we get the multiples of 643 which are 643, 1286, 1929…and so on.
About the number 643:
- 643 has only two factors which are 1 and the number itself and hence 643 is the prime number.
- 643 is the odd prime number and it is not the perfect square also.
- If we divide 643 by 1 and the number itself then we get remainder as zero. Hence, 1 and 643 are the factors of 643.
Note:
- 643 is not the perfect square.
- Factors of 643: 1 and 643
- Prime factors of 643: 643 (since, 643 is the only one prime number which is the factor of 643.)
Conclusion:
- 643 is the prime number which has factors 1 and 643.
- And hence, 643 is the prime number.
Multiple Choice Questions:
1) 643 is a
a) odd number
b) Prime number
c) Composite number
d) Both a and b
Ans: d) both a and b
2) The prime factors of a prime number 643 are
a) 1
b) 643
c) Both a and b
d) 0
Ans: b) 643
3) 1 is the not prime factor of 643 because
a) It is the prime number
b) 1 is neither prime nor composite number
c) Both a and b
d) Given statement is false
Ans: b) 1 is neither prime nor composite number