The largest known prime number has 41,024,320 digits — printed at normal size, it would run for over 100 miles.

The largest known prime number, 2^136,279,841−1, has 41,024,320 digits and was found on October 12, 2024 by Luke Durant, a former Nvidia employee running thousands of cloud GPUs across 17 countries.

The largest prime number anyone has ever verified is 2^136,279,841−1. Write it out at normal size and the digits — all 41,024,320 of them — would run for more than 100 miles. Its name, in the shorthand of prime hunters, is M136279841, and it was confirmed prime on October 12, 2024.

What makes this record different isn't just its size. It's who found it, and how. For 28 straight years, the largest known prime had always been discovered on an ordinary personal computer — someone's desktop grinding away in a spare bedroom. This one wasn't.

Who found the largest known prime, and how

The discoverer is Luke Durant, a 36-year-old former Nvidia employee from San Jose, California. Instead of a home PC, Durant assembled what the Great Internet Mersenne Prime Search (GIMPS) called a "cloud supercomputer" — thousands of graphics processing units spread across 24 datacenter regions in 17 countries, all pointed at the same problem.

The first signal came from an Nvidia A100 GPU running in Dublin, which flagged the number as a "probable prime" on October 11, 2024. The claim was then handed to a second, independent machine — an Nvidia H100 in San Antonio, Texas — which confirmed the result the next day. Two different chips on two different continents had to agree before anyone would call it real.

In its official announcement — titled "2^136279841−1 is Prime! / 52nd Known Mersenne Prime Discovered" — GIMPS marked the moment plainly: "This prime ends the 28 year reign of ordinary PCs finding the largest known prime." Smithsonian Magazine reported the same details, noting Durant's network of thousands of GPUs across 24 data centers in 17 countries, and the German technology outlet heise online confirmed the discovery date and the Dublin A100 that first raised the flag.

Why Mersenne primes and why GPUs

The number belongs to a special family called Mersenne primes — primes that are exactly one less than a power of two. They matter to hunters for a practical reason: there's a fast, well-understood test, the Lucas–Lehmer test, that can prove whether a Mersenne candidate is prime without checking it against every possible divisor. That test is what makes searching millions of digits deep even conceivable.

For decades, GIMPS ran on volunteer CPUs — the central processors in home computers. Durant's contribution was to move the hunt onto GPUs, the same chips that power video games and, more recently, artificial intelligence. A GPU can run enormous numbers of calculations in parallel, and modern datacenters rent them out by the hour. Durant essentially bought supercomputer time the way you'd rent a car, and turned it loose on a mathematical question with no practical payoff at all.

That's worth sitting with. There is no engineering use for a 41-million-digit prime. Cryptography, which does rely on primes, uses numbers thousands of times smaller. This record exists because a person wanted to know whether a particular number could be split into smaller factors, and the answer — after all that machinery in all those countries — was no.

What's still open

The obvious question is whether this even counts as the same pursuit anymore. GIMPS framed the discovery as the end of an era, and there's real melancholy in that phrasing. The romance of the amateur at the home computer — the retiree, the teacher, the student who left a program running overnight and woke up in the record books — collided with the plain fact that rented industrial hardware is simply faster.

Durant is, technically, still an amateur working through a volunteer project. But the tool changed the game. The next largest prime will almost certainly come from a datacenter, not a desk.

And nobody knows how many Mersenne primes there are — whether they run on forever or eventually stop. That question, unlike this record, no amount of rented silicon has yet been able to settle.