No, 9 is not a perfect number.
A perfect number is a positive integer that is equal to the sum of its proper divisors (the positive divisors excluding the number itself). Let's examine the divisors of 9:
- Divisors of 9: 1, 3, and 9
The proper divisors of 9 are 1 and 3. The sum of these proper divisors is 1 + 3 = 4. Since 4 is not equal to 9, 9 does not meet the criteria to be a perfect number.
In contrast, consider the perfect number 6. Its divisors are 1, 2, 3, and 6. Its proper divisors are 1, 2, and 3. The sum of its proper divisors is 1 + 2 + 3 = 6. Therefore, 6 is a perfect number.
