If we list the factors of 29, we only have 1 and 29. For example, if we list the factors of 28, we have 1, 2, 4, 7, 14, and 28. We’ll start with an anonymous question from 1995: Prime Numbersĭoctor Ken answered with the definition and a pair of examples: Hello!Ī prime number is a positive number that has exactly two factors, 1 and itself. I’ll begin a short series of posts on prime numbers with several questions on the basics: What are prime (and composite) numbers, and why do they matter?
