The smallest prime number is 2, the smallest composite number is 4, and the smallest natural number is 0, so (2+4) × 0 = 0 prime number: that is, all integers greater than 1 have no divisor except 1 and itself. This integer is called prime number, and prime number is also called prime number.

Composite number: The divisor of a number has other divisors besides 1 and itself. This number is called a composite number.

Even number, in an integer, the number divisible by 2 is even, and vice versa. Even numbers can be represented by 2k, and odd numbers can be represented by 2k+ 1

Where 1 is neither a prime number nor a composite number. 2 is an even number and a prime number. Positive integers can be divided into three categories according to whether they are divisible by numbers other than 1 and themselves.

Prime numbers (prime numbers) can only be divisible by 1 and itself, such as 2, 3, 5, 7, 1 1, 13, ...

The composite number can be divisible by itself and numbers other than 1, such as 4, 6, 8, 9, 10, ...

1 is neither a prime number nor a number (only 1 itself).

A composite number is the product of two or more different numbers. It can be proved that there are infinitely many prime numbers and composite numbers. But in comparison, the number of prime numbers is very small, while the composite numbers are many. It can be said that positive integers are almost entirely composed of composite numbers, but prime numbers (prime numbers) are the elements that constitute composite numbers (hence the name prime numbers). In mathematics, prime numbers are more important than composite numbers, so that as long as a number is found to be prime (of course, others don't know), it can be regarded as a paper.