Is 1981 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 1981 is composite or not first we have to find its factors.
Contents
Factors of 1981:
- If we have taken numbers from 1, 2, 3…for checking factors of 1981, we found that 1981 has factors 1, 7, 283 and 1981. Hence, we must say that 1981 is a composite number.
- Thus, 1981 is the composite number.
- If we multiply 1981 by 1, 2, 3 then we get the multiples of 1981 which are 1981, 3962 and so on.
1981 is a Composite number or Prime number
About the number 1981:
- 1981 has more than two factors which are 1, 7, 283 and 1981 and hence it is the composite number.
- 1981 is the odd composite number and it is not the perfect square also.
- If we divide 1981 by 1, 7, 283 and 1981 then we get remainder as zero. Hence, 1, 7, 283 and 1981 are the factors of 1981
Note:
- 1981 is not the perfect square.
- Factors of 1981: 1, 7, 283 and 1981
- Prime factors of 1981: 7, 283
Conclusion:
- 1981 is the composite number which has factors 1, 7, 283 and 1981.
- And hence, 1981 is not the prime number.
Multiple Choice Questions:
1) 1981 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 1981 are
a) 1
b) 7, 283
c) 1 and 1981
d) 1, 7, 283 and 1981
Ans: c) 1 and 1981
3) 1981 is the odd composite number because
a) It has factors 1, 7, 283 and 1981
b) It has more than two factors
c) It is not divisible by 2
d) all
Ans: d) all