Related attributes:
Divisibility: If the integer A is divisible by the non-zero integer B, the quotient is an integer and the remainder is zero, we say that A is divisible by B (or B is divisible by A) and it is recorded as B | A. ..
Prime number (prime number): A natural number with exactly two positive factors. (or defined as a number that cannot be divisible by other natural numbers except 1 and the integer itself among natural numbers greater than 1).
Composite number: There are other positive factors besides 1 and itself.
1 has only a positive factor of 1, so it is neither a prime number nor a composite number.
If A is a factor of B and A is a prime number, then A is a prime factor of B ... For example, 2, 3 and 5 are all prime factors of 30. 6 is not a prime number, so it doesn't count. 7 is not a factor of 30, so it is not a prime factor.
Two nonzero natural numbers whose common factor is only 1 are called coprime numbers.
The number of positive factors of 1 nonzero natural number is limited, of which the smallest is 1 and the largest is itself. The multiples of nonzero natural numbers are infinite.