Is 640 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 640 is composite or not first we have to find its factors.
Contents
Factors of 640:
- If we have taken numbers from 1, 2, 3…for checking factors of 640, we found that 640 has factors 1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 128, 160, 320 and 640. Hence, we must say that 640 is a composite number.
- Thus, 640 is the composite umber.
- If we multiply 640 by 1, 2, 3 then we get the multiples of 640 which are 640, 1280 and so on.
About the number 640:
- 640 has more than two factors which are 1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 128, 160, 320 and 640 and hence it is the composite number.
- 640 is the even composite number and it is not the perfect square also.
- If we divide 640 by 1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 128, 160, 320 and 640 then we get remainder as zero. Hence, 1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 128, 160, 320 and 640 are the factors of 640.
Note:
- 640 is not the perfect square.
- Factors of 640: 1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 128, 160, 320 and 640
- Prime factors of 640: 2, 5
Conclusion:
- 640 is the composite number which has factors 1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 128, 160, 320 and 640
- And hence, 640 is not the prime number.
Multiple Choice Questions:
1) 640 is a
a) Not a perfect square number
b) Even number
c) Composite number
d) all
Ans: d) all
2) The prime and composite factors of a composite number 640 are
a) 1
b) 2, 5
c) 1, 4, 8, 10, 16, 20, 32, 40, 64, 80, 128, 160, 320 and 640
d) 1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 128, 160, 320 and 640
Ans: d) 1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 128, 160, 320 and 640
3) 640 is the even composite number because
a) It has factors 1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 128, 160, 320 and 640
b) More than two factors
c) Divisible by 2
d) all
Ans: d) all