Professor Cardy

Prime Number Calculator

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Enter an integer (max. 1,000,000)


38113 is a prime number.

About the Calculator

This calculator performs the decomposition of a number into its prime factors and lists all its natural divisors. Enter an integer between 1 and 1,000,000.

Curiosities

1) Relation to multiples of 6: Every prime number greater than 3 is always one less or one more than a multiple of 6.
Example: `38113` is 1 more than `38112` (multiple of 6).

2) Square minus 1 divisible by 24: For every prime number greater than 3, if 1 is subtracted from its square, the result is always divisible by 24.
Example: The square of `38113` is `1452600769`. Subtracting 1, we get `1452600768`. Note that `1452600768 ÷ 24 = 60525032`.

3) Difference of squares: Every prime number greater than 2 can be expressed as the difference of the squares of two consecutive natural numbers.
Example: `38113 = 19057^2 - 19056^2 = 363169249 - 363131136`

4) Sum of two squares: Every prime number of the form `4n+1` (where n is a positive natural number) can be expressed as the sum of two squares.
Example: `38113 = 68^2 + 183^2 = 4624 + 33489`, where `38113 = 4 × 9528 + 1`.

5) Form `4n+1` or `4n-1`: Except for the number 2, all prime numbers follow the pattern `4n+1` or `4n-1`, where `n` is a natural number.
Example: `38113` is of the form `4n+1`, where `n = 9528`.

The First 10,000 Prime Numbers