Prime Number Calculator

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: `20021` is 1 less than `20022` (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 `20021` is `400840441`. Subtracting 1, we get `400840440`. Note that `400840440 ÷ 24 = 16701685`.

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: `20021 = 10011^2 - 10010^2 = 100220121 - 100200100`

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: `20021 = 89^2 + 110^2 = 7921 + 12100`, where `20021 = 4 × 5005 + 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: `20021` is of the form `4n+1`, where `n = 5005`.