23 is the only known number p where R p is a repunit prime 10p-p is prime and p is a prime factor of a Mersenne number with repunit exponent. The number 23 is a prime number because it is not possible to factorize it. Prime Number List Prime Number Chart From 1 To 100 And Up To 500 Posters Math Interactive Math Classroom Math Interactive Notebook In other words 23 is only divided by 1 or by itself. . 23 and then click. In other words 23 is only divided by 1 or by itself. A prime number is a natural number greater than 1 that is not a product of two smaller natural numbers. It is possible to find out using mathematical methods whether a given integer is a prime number or not. Here you can find the answer to questions related to. This is a list of articles about prime numbersA prime number or prime is a natural number greater than 1 that has no positive divisors other than 1 and itself. Solved Problems on 23