Is 81 a prime number or a composite number?
Understand the Problem
The question is asking us to determine whether the number 81 is prime or composite. A prime number has exactly two distinct positive divisors (1 and itself), while a composite number has more than two positive divisors. We will check the divisors of 81.
Answer
composite number
The final answer is composite number.
Answer for screen readers
The final answer is composite number.
More Information
81 can be factored into smaller numbers: 81 = 9 x 9 or 81 = 3 x 3 x 3 x 3. Therefore, it is not a prime number.
Tips
A common mistake is not exploring all factor combinations. Always check if a number can be divided by any integer other than 1 and itself.