99 is a prime number

Calculator: prime number test

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Online program for analyzing natural numbers for prime numbers with incremental prime factorization and powers

You can enter natural numbers up to 16 digits to have. For example: 1 234 567 890 123 456

Enter any natural number. Immediately it is calculated whether it is prime and its prime factors are displayed.

Tip: keys and for incremental value changes

Step-by-step determination of the prime factors: Calculation method prime number

Prime Numbers Calculator: These are the formulas for calculating prime numbers.

See article Prime Numbers

What are prime numbers?


Prime numbers are all natural numbers that are only divisible by 1 and themselves. The 2 is the prime number, it is the smallest and the only even prime number.

Why is one not a prime number?

A prime number is only divisible by 1 and is divisible by itself. One says that dividing by 1 is one factor and dividing by itself is the other factor, that is, it is about two different dividers. And the number 1 would be divisible by 1 and then by itself, so again 1. That means we only have one equal factor and not two different ones! Therefore, the 1 is not a prime number and is excluded by definition.

Word origin

The word "prim" comes from the Latin "prima", which in turn comes from "primus" and means "first, foremost". This designation was probably chosen because every natural number consists of prime numbers that can be broken down.

25 prime numbers from 1 to 100:

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

How does the program on this website calculate?

The program goes through all numbers from 2 to the value of the entered number and checks whether the entered number is divisible without a remainder. If this is the case, the valid divisor is saved and output as a prime factor. If the program does not find any divisors, then it is obviously a prime number. In addition to the 2, only odd numbers are checked, since every even number greater than 2 is divisible by 2 and therefore cannot be a prime number.

List of prime numbers up to 100,000

Calculator prime numbers, prime number calculator