25 = 5 * 5 In other words, 25’s “prime signature” is 5 * 5. Only 25 has that signature and 5 * 5 only comes out to 25. If you think about the entire range of whole numbers—that is, the ...

For instance, the largest known prime number, which is 2 136279841 − 1, is 41,024,320 digits long. At first, that number may seem mind-bogglingly large.

Both arithmetic aficionados and the mathematically challenged will be equally captivated by new research that upends hundreds of years of popular belief about prime numbers.

2. 3. 5. 7. 11. 13. 17. And so on. This is far from a comprehensive list of prime numbers—if we were to compile and write out an exhaustive list of all known prime numbers, this would be a truly ...

If N is a prime number, then bN – b is always a multiple of N, no matter what b is. For instance, 7 is a prime number, and as a result, 2 7 – 2 (which equals 126) is a multiple of 7. Similarly, 3 7 – ...

In the years that followed, Sloane's catalog of number sequences got bigger. In 1995 the mathematician, together with his colleague Simon Plouffe, published The Encyclopedia of Integer Sequences ...

Rational numbers, which make up the majority of numbers we use in day-to-day life (although less than half of all possible numbers), can be written in the form of one whole number divided by another.