Prime Numbers

A number that has no positive integer divisors other than one and itself is called a normal number.

Prime Numbers Among Themselves

At least two integers that have no positive common integer divisor other than 1 are called primes between them.

4, 9, 13, 27 are prime between them.

With 1, all numbers are prime between them.

Consecutive counting numbers are prime between themselves.

Not all numbers that are prime between each other have to be prime numbers.