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This article will explain in detail how php judges primes. The editor thinks it is very practical, so I share it with you as a reference. I hope you can get something after reading this article.

1. The easiest way is to find it according to the definition of prime.

A prime can only be divisible by 1 and itself, that is, it can only be divisible twice.

So we use a loop to remove N from every natural number greater than 1 and less than or equal to N, and count the number of times divisible. If the number is greater than 2, it is not a prime; if it is equal to 2, it is a prime.

2. Divide a number from 2 to sqrt (this number). If it is divisible, it shows that the number is not a prime number, on the contrary, it is a prime number.

This is the end of the article on "how to judge primes by php". I hope the above content can be helpful to you so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

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