A prime number is a natural number of 2 or more that does not have a positive divisor other than 1 and the number itself. For example, 2, 3, 5, 7, etc. correspond to prime numbers.

Definition of prime numbers

A prime number is a natural number with only two positive divisors, “1 and its number itself”. A natural number of 2 or more that is not a prime number is called a composite number.

Example of prime numbers

Specific prime numbers include the following.

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97

The reason why 1 is not a prime number

1 is not included in prime numbers because there is only one positive dicidant. Because the definition of a prime number is “a natural number with two positive dicisors”.

How to distinguish prime numbers

To determine whether a number is a prime number, there is a way to divide the number by a small number.

Check if they can be divisible by 2: All even numbers other than 2 are not prime numbers because they are divisible by 2.

Check if it is divisible by 3: If the sum of each digit is divisible by 3, the number is not a prime number because it is divisible by 3.

Check if it can be divisible by 5: A number with a digit of 0 or 5 is not a prime number because it can be divisible by 5.

Trial division: Divide in order by prime numbers from 2 to the square root of that number, and find out if there is a number that can be divided. If there is no divisible number, it is a prime number.

Properties of prime numbers

The smallest prime number is 2.

It was proven by Euclid about the 3rd century BC that prime numbers exist infinity.

The distribution of prime numbers is related to important problems in modern mathematics.

素数が未来を変えます。もちろん自分でコントロールできる！0-1も存在致します。現世では0-1が大切です。未来視致します！！

導きます。

土屋梨沙