We've all learnt about prime numbers in school and for those who don't remember it's a number that's divisible by no other number other than 1 and itself. And now there's a new prime number that is the largest ever discovered.

According to a Huffington Post report, Dr Curtis Cooper from the University of Central Missouri has discovered the largest known prime number which is nearly 22 million digits long. It is a whopping 5 million digits longer than the last prime number discovered.

Representational image | Source: Reuters

The newly discovered number is written as (2^74,207,281)-1, which mathematically means two multiplied by itself 74,207,280 times and finally the product will be subtracted by one.

Prime numbers play a crucial role in computer encryption, and assure security while banking, shopping and messaging online. But as this BBC report says, the new largest prime number has little use since the numbers used presently in encryption run into hundreds of digits and not in millions.

Representational image | Source: Reuters

The new prime number was discovered by the Great Internet Mersenne Prime Search (GIMPS), which is a quest using computers to find a certain range of large prime numbers. In this project prime numbers are hunted by multiplying two with itself a large number of times and then subtracting one, much like in the case of the largest prime number.

And despite seeming pretty useless and merely consuming processor time, it turns out the quest for prime numbers does help in detecting errors in processors as well.