Professor Cardy

Prime Number Calculator

PORTUGUESE ENGLISH SPANISH FRENCH GERMAN CHINESE

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


103913 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: `103913` is 1 less than `103914` (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 `103913` is `10797911569`. Subtracting 1, we get `10797911568`. Note that `10797911568 ÷ 24 = 449912982`.

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: `103913 = 51957^2 - 51956^2 = 2699529849 - 2699425936`

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: `103913 = 173^2 + 272^2 = 29929 + 73984`, where `103913 = 4 × 25978 + 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: `103913` is of the form `4n+1`, where `n = 25978`.

The First 10,000 Prime Numbers