Prime numbers: what’s the big deal?


Prime numbers keep your money secure What's in your wallet? Cash, plastic and lots of prime…

Georgia (Feb 12, 2013)Prime numbers keep your money secure

What's in your wallet? Cash, plastic and lots of prime numbers

You may not be a billionaire or even a millionaire, but the discovery of the largest known prime number -- 2 to the 57,885,161 power, minus 1 – will help keep hackers from stealing money from your bank accounts, and credit and debit cards.

Kennesaw State University mathematics professor Joe DeMaio says size matters when it comes to encrypting financial information and keeping it out of the hands of the bad guys.

It’s really hard to factor large numbers – even with the speed of modern computers. Hackers could intercept your encoded information but they won’t be able to decrypt it.

“The difficulty of factoring the product of two large prime numbers is the basis of RSA encryption and public-key cryptography,” DeMaio says. “If you like the secure use of your credit card number while shopping on the Internet then large primes are important.”

The computing collaborative known as Great Internet Mersenne Prime Search (GIMPS) recently announced that the largest known prime number has been calculated by Curtis Cooper, a professor of computer science at the University of Central Missouri.

And it’s really big. It has 17,425,170 digits.

“There are larger primes in existence but we don't know what they are yet,” DeMaio says.

If you remember your math classes, a prime number is a positive number that can be divided only by itself and 1. The number five is a prime, since it can only be divided by itself and 1. But the number 8 is not. It can be divided by: 1, 2, 4 and 8.

Large prime numbers can also be used for quality control. Calculating large prime numbers take an enormous amount of computations.  If the answer comes up wrong, there could be a problem with the hardware.

“This is how a mathematician working with large primes found a flaw Intel's Pentium chip in 1994,” DeMaio says. “If you want your computer to perform correctly, then large primes are an important part of quality assurance.”

-Yolanda Rodriguez


A leader in innovative teaching and learning, Kennesaw State University offers undergraduate, graduate and doctoral degrees to its nearly 43,000 students. With 11 colleges on two metro Atlanta campuses, Kennesaw State is a member of the University System of Georgia. The university’s vibrant campus culture, diverse population, strong global ties and entrepreneurial spirit draw students from throughout the country and the world. Kennesaw State is a Carnegie-designated doctoral research institution (R2), placing it among an elite group of only 6 percent of U.S. colleges and universities with an R1 or R2 status. For more information, visit