Is 405 is a composite 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 405 is composite or not first we have to find its factors.
Contents
Factors of 405:
- If we have taken numbers from 1, 2, 3…for checking factors of 405, we found that 405 has factors 1, 3, 5, 9, 15, 27, 45, 81, 135 and 405. Hence, we must say that 405 is a composite number.
- Thus, 405 is the composite number.
- If we multiply 405 by 1, 2, 3 then we get the multiples of 405 which are 405, 810 and so on.
405 is a Composite number or Prime number
About the number 405:
- 405 has more than two factors which are 1, 3, 5, 9, 15, 27, 45, 81, 135 and 405 and hence it is the composite number.
- 405 is the odd composite number and it is not the perfect square also.
- If we divide 405 by 1, 3, 5, 9, 15, 27, 45, 81, 135 and 405 then we get remainder as zero. Hence, 1, 3, 5, 9, 15, 27, 45, 81, 135 and 405 are the factors of 405.
Note:
- 405 is not the perfect square.
- Factors of 405: 1, 3, 5, 9, 15, 27, 45, 81, 135 and 405
- Prime factors of 405: 3, 5
Conclusion:
- 405 is the composite number which has factors 1, 3, 5, 9, 15, 27, 45, 81, 135 and 405.
- And hence, 405 is not the prime number.
Multiple Choice Questions:
1) 405 is a
a) odd number
b) Prime number
c) Composite number
d) Both a and c
Ans: d) both a and c
2) The prime factors of a composite number 405 are
a) 1
b) 3, 5
c) 1, 9, 15, 27, 45, 81, 135 and 405
d) 1, 3, 5, 9, 15, 27, 45, 81, 135 and 405
Ans: b) 3, 5
3) 405 is the odd composite number because
a) It has factors 1, 3, 5, 9, 15, 27, 45, 81, 135 and 405
b) It is divisible by 2
c) It is not divisible by 2
d) Both a and c
Ans: d) both a and c