Professor Cardy

Prime Number Calculator

PORTUGUESE ENGLISH SPANISH FRENCH GERMAN CHINESE

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


79279 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: `79279` is 1 more than `79278` (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 `79279` is `6285159841`. Subtracting 1, we get `6285159840`. Note that `6285159840 ÷ 24 = 261881660`.

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: `79279 = 39640^2 - 39639^2 = 1571329600 - 1571250321`

4) 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: `79279` is of the form `4n-1`, where `n = 19820`.

The First 10,000 Prime Numbers