64 is a composite number. By definition, a prime number is a number greater than 1 that has no positive divisors other than 1 and itself. In contrast, a composite number has more than two distinct positive divisors.
In the case of 64, it can be expressed as the product of smaller integers: 64 = 8 × 8 = 2 × 2 × 2 × 2 × 2 × 2, which shows that it has multiple factors, including 1, 2, 4, 8, 16, 32, and 64 itself. Since 64 can be divided evenly by these numbers, it confirms that it is not a prime number, but rather a composite number.