A human obsession with large numbers

We humans are a competitive species, forever looking for something bigger, faster or just better than the rest. We seek gold medals, fame and fortune (or a bonus, at least). Our targets invariably involve measurements — of distance, time, money, speed or whatever. In short, we are obsessed with numbers.

One particular type of number has attracted a lot of attention recently, the largest prime number. A prime number is one that is only divisible by itself or by one. These numbers are important (trust me). They apply to everything from David Beckham’s football shirt to the encoding of credit card numbers.

In theory you can search into infinity for the largest one but as they get bigger they take a lot of time, computer power and expertise to find.

The most recent largest prime number is 2^43,112,609–1, which has 12,978,189 digits. Numbers that take the form 2ⁿ–1 are known as Mersenne numbers, but few of them are prime numbers and the new number is only the 46th Mersenne prime to be found.

The team who found it are claiming a US$100,000 prize offered by the Electronic Frontier Foundation for the first prime with more than 10,000,000 digits. Someone, somewhere will already be looking for a bigger one.