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Filling the gaps: Microsoft contest locates new prime numbers

Prime numbers are endlessly fascinating to computing and math fans, and there's an infinite supply of them. A Microsoft contest succeeds in fleshing out the list of primes that aren't actually the largest.

Stephen Shankland Former Principal Writer
Stephen Shankland worked at CNET from 1998 to 2024 and wrote about processors, digital photography, AI, quantum computing, computer science, materials science, supercomputers, drones, browsers, 3D printing, USB, and new computing technology in general. He has a soft spot in his heart for standards groups and I/O interfaces. His first big scoop was about radioactive cat poop.
Expertise Processors, semiconductors, web browsers, quantum computing, supercomputers, AI, 3D printing, drones, computer science, physics, programming, materials science, USB, UWB, Android, digital photography, science. Credentials
  • Shankland covered the tech industry for more than 25 years and was a science writer for five years before that. He has deep expertise in microprocessors, digital photography, computer hardware and software, internet standards, web technology, and more.
Stephen Shankland
2 min read

The Microsoft Prime Challenge is a contest designed to find not the largest previously unknown prime, but to find primes in gaps that previously hadn't been scrutinized.
The Microsoft Prime Challenge is a contest designed to find not the largest previously unknown prime, but to find primes in gaps that previously hadn't been scrutinized. Microsoft

A contest to promote technical education and Microsoft's cloud-computing infrastructure has turned up a previously unknown prime number more than 342,000 digits long -- and a bunch of other smaller ones.

The Microsoft Prime Challenge contest winner, a US resident who goes by the username PHunterLau, also turned up at least four other primes in the contest. The object of the competition was not to find the largest prime ever, but instead to find primes within the wide swaths of unexplored territory that current prime-number search techniques don't scrutinize.

To perform their prime search, contestants got $200 worth of time on Microsoft Azure, the company's cloud-computing infrastructure that competes with Amazon Web Services, Google Compute Engine, Rackspace Public Cloud, and more.

Azure is a key part of Microsoft's attempt to extend the market strength of its Windows operating system to new-era computing approaches, including the cloud computing approaches in which customers rent capacity from a company that has thousands of servers available.

The Microsoft Prime Challenge promotes the company's cloud-computing infrastructure.
The Microsoft Prime Challenge promotes the company's cloud-computing infrastructure. Microsoft

But Azure doesn't just run Windows -- a variety of Linux versions are also supported. Microsoft now appears to be going even further beyond its philosophy that Windows should be every customer's solution to any computing problem.

For example, it's just released Microsoft Office for iPad, and it's renaming Windows Azure to Microsoft Azure.

Prime numbers, which are numbers larger than 1 that can be evenly divided only by 1 and themselves, have been mathematical curiosities for centuries and more recently have attained relevance in the computing industry as a foundation for encryption technology. And for decades, individuals and teams have strived to find ever-larger primes.

The largest known prime thus far is 2^57,885,161-1, which is a 17,425,170-digit number. The Electronic Frontier Foundation offers a $150,000 prize to anyone who can discover a prime more than 100 million digits long and a $250,000 prize for one more than a billion digits long.