Is 1989 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 1989 is composite or not first we have to find its factors.
Contents
Factors of 1989:
- If we have taken numbers from 1, 2, 3…for checking factors of 1989, we found that 1989 has factors 1, 3, 9, 13, 17, 39, 51, 117, 153, 221, 663 and 1989. Hence, we must say that 1989 is a composite number.
- Thus, 1989 is the composite number.
- If we multiply 1989 by 1, 2, 3 then we get the multiples of 1989 which are 1989, 3978 and so on.
1989 is a Composite number or Prime number
About the number 1989:
- 1989 has more than two factors which are 1, 3, 9, 13, 17, 39, 51, 117, 153, 221, 663 and 1989 and hence it is the composite number.
- 1989 is the odd composite number and it is not the perfect square also.
- If we divide 1989 by 1, 3, 9, 13, 17, 39, 51, 117, 153, 221, 663 and 1989 then we get remainder as zero. Hence, 1, 3, 9, 13, 17, 39, 51, 117, 153, 221, 663 and 1989 are the factors of 1989
Note:
- 1989 is not the perfect square.
- Factors of 1989: 1, 3, 9, 13, 17, 39, 51, 117, 153, 221, 663 and 1989
- Prime factors of 1989: 3, 13, 17
Conclusion:
- 1989 is the composite number which has factors 1, 3, 9, 13, 17, 39, 51, 117, 153, 221, 663 and 1989.
- And hence, 1989 is not the prime number.
Multiple Choice Questions:
1) 1989 is a
a) Even number
b) Prime number
c) Composite number
d) Both a and c
Ans: c) composite number
2) The non-prime factors of a composite number 1989 are
a) 1
b) 3, 13, 17
c) 1, 9, 39, 51, 117, 153, 221, 663 and 1989
d) 1, 3, 9, 13, 17, 39, 51, 117, 153, 221, 663 and 1989
Ans: c) 1, 9, 39, 51, 117, 153, 221, 663 and 1989
3) 1989 is the odd composite number because
a) It has factors 1, 3, 9, 13, 17, 39, 51, 117, 153, 221, 663 and 1989
b) It has more than two factors
c) It is not divisible by 2
d) all
Ans: d) all