What is an example of a prime number?

Could you please explain to me, with a clear example, what exactly a prime number is? I've heard the term mentioned in various contexts but I'm still not quite sure how to identify one. Could you provide me with a simple yet illustrative instance of a prime number that would help me grasp the concept better? I'm really interested in understanding the mathematical properties of prime numbers and how they fit into the broader field of numbers and cryptography. Thank you in advance for your assistance!