2, 3, 5, 7, 1 1, 2, 3, 5, 7 and 1 1

13, 17 Thirteen is followed by seventeen.

19, 23, 29 19, 23, 29

3 1, 37,41Sany, Sanqi, Forty-one

43, 47, 53, 43, 47, 53

59, 6 1, 67 59, 6 1, 67

7 1, 73, July 79 1 day, 73, 79

83, 89, 97 83, 89, 97

25 prime numbers are indispensable: remember the prime numbers within 100.

A prime number is a natural number that can only be divisible by 1 and itself, that is, no other factor can divide it except 1 and itself. Prime number is a very important concept in mathematics, which has unique properties and characteristics.

Prime numbers are infinite, that is, the number of prime numbers is infinite. No matter how many prime numbers we find, we can always find more prime numbers. This property is called sparsity of forest prime numbers.

Prime numbers are widely used in the fields of number theory and cryptography. The proof and application of Fermat's last theorem and Euler's last theorem in number theory are inseparable from prime numbers. In cryptography, the product of prime numbers is used to generate secure public and private keys to ensure the security of communication.

The judgment and decomposition of prime numbers is an important problem in number theory. To judge whether a number is a prime number, we can use trial and error division, prime number screening and other methods. To decompose a composite number into a product of prime numbers, it is necessary to use the factorization theorem of prime numbers, which is of great significance to many problems in mathematics.

The famous Eratosthenes prime number screening method is an effective algorithm to find all the prime numbers in a certain range. Through this algorithm, a large number of prime numbers can be found in a relatively fast time, which is helpful to further study the laws and properties of prime numbers.

Concepts of prime numbers and composite numbers

A prime number is a natural number greater than 1, and no other positive factor can divide it except 1 and itself. In other words, a prime number can only be divisible by 1 and itself, with no other factors. For example, 2, 3, 5, 7, 1 1 are prime numbers. Prime numbers are infinite, that is, the number of prime numbers is infinite.

Composite number refers to a natural number greater than 1. Besides 1 and itself, there are other positive factors that can accurately divide it. In other words, the composite number has at least one factor other than 1 and itself. For example, 4, 6, 8, 9, 12 are all plural numbers.