Is 1820 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 1820 is composite or not first we have to find its factors.
Factors of 1820:
- If we have taken numbers from 1, 2, 3…for checking factors of 1820, we found that 1820 has factors 1, 2, 4, 5, 7, 10, 13, 14, 20, 26, 28, 35, 52, 65, 70, 91, 130, 140, 182, 260, 364, 455, 910 and 1820. Hence, we must say that 1820 is a composite number.
- Thus, 1820 is the composite number.
- If we multiply 1820 by 1, 2, 3 then we get the multiples of 1820 which are 1820, 3640 and so on.
About the number 1820:
- 1820 has more than two factors which are 1, 2, 4, 5, 7, 10, 13, 14, 20, 26, 28, 35, 52, 65, 70, 91, 130, 140, 182, 260, 364, 455, 910 and 1820 and hence it is the composite number.
- 1820 is the even composite number and it is not the perfect square also.
- If we divide 1820 by, 1, 2, 4, 5, 7, 10, 13, 14, 20, 26, 28, 35, 52, 65, 70, 91, 130, 140, 182, 260, 364, 455, 910 and 1820 then we get remainder as zero. Hence, 1, 2, 4, 5, 7, 10, 13, 14, 20, 26, 28, 35, 52, 65, 70, 91, 130, 140, 182, 260, 364, 455, 910 and 1820 are the factors of 1820.
Note:
- 1820 is not the perfect square.
- Factors of 1820: 1, 2, 4, 5, 7, 10, 13, 14, 20, 26, 28, 35, 52, 65, 70, 91, 130, 140, 182, 260, 364, 455, 910 and 1820
- Prime factors of 1820: 2, 5, 7, 13
Conclusion:
- 1820 is the composite number which has factors 1, 2, 4, 5, 7, 10, 13, 14, 20, 26, 28, 35, 52, 65, 70, 91, 130, 140, 182, 260, 364, 455, 910 and 1820
- And hence, 1820 is not the prime number.
Multiple Choice Questions:
1) 1820 is a
a) Prime number
b) Odd number
c) Composite number
d) Both a and c
Ans: c) composite number
2) The non-prime factors of a composite number 1820 are
a) 1820
b) 2, 5, 7, 13
c) 1, 4, 10, 14, 20, 26, 28, 35, 52, 65, 70, 91, 130, 140, 182, 260, 364, 455, 910 and 1820
d) 1, 2, 4, 5, 7, 10, 13, 14, 20, 26, 28, 35, 52, 65, 70, 91, 130, 140, 182, 260, 364, 455, 910 and 1820
Ans: c) 1, 4, 10, 14, 20, 26, 28, 35, 52, 65, 70, 91, 130, 140, 182, 260, 364, 455, 910 and 1820
3) 1820 is composite number because
a) It has factors 1, 2, 4, 5, 7, 10, 13, 14, 20, 26, 28, 35, 52, 65, 70, 91, 130, 140, 182, 260, 364, 455, 910 and 1820
b) It has only two factors
c) Divisible by 2
d) Both a and c
Ans: a) it has factors 1, 2, 4, 5, 7, 10, 13, 14, 20, 26, 28, 35, 52, 65, 70, 91, 130, 140, 182, 260, 364, 455, 910 and 1820