1. The problem is to understand the number 13 and explain its properties. 2. 13 is a natural number that comes after 12 and before 14. 3. It is a prime number, which means it has no divisors other than 1 and itself. 4. Prime numbers are important in mathematics because they are the building blocks of all natural numbers. 5. To check if 13 is prime, we test divisibility by numbers less than its square root (which is approximately 3.6). 6. 13 is not divisible by 2 or 3, so it is prime. 7. Therefore, 13 is a prime number with factors 1 and 13 only.