Why isn t 2001 a prime number?

Why isn't 2001 considered a prime number? Isn't it supposed to be a number that's only divisible by 1 and itself? What makes it different from other prime numbers like 2, 3, 5, or 7? Is there a specific rule or criteria that 2001 doesn't meet? Can you explain the mathematical reasoning behind why 2001 is not a prime number in a clear and concise manner?