A new prime number, 23 million digits long

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An online pubic program designed to allow ordinary people to use their computers to identify previously unknown prime numbers has found the largest so far, 23 million digits long.

It was discovered on December 26, 2017 by electrical engineer Jonathan Pace, and it initially took six days of non-stop number crunching to show that it was indeed a prime number. Pace was using a consumer-level PC running an Intel i5-6600 processor, and after it was identified it was then independently verified by other users, with a range of other programs and hardware setups.



  • wayne

    A History of Primes –
    Dr. Manindra Agrawal
    -American Academy of Arts and Sciences, October 2002

  • Garry

    The first computer program I ever wrote (in the late 70’s, when I was about 13) printed out the prime numbers in order. I used a PDP-11 computer, which I seem to remember was the size of a large refrigerator and kept in its own sealed, climate controlled space, and programmed BASIC (I forgot what version). My innovation was checking prime factors up to the integer square root of the number in question; my instructor had told me to check all numbers up to the number itself.

    I remember being excited when it quickly spit out 2, 3, 5, but when it got in the 30’s it slowed down considerably, and it took maybe 10 minutes to reach the 200’s.

    My career in programming didn’t last much longer than that.

    Sometimes I forget how far and how fast computers have advanced.

  • Lee S

    I’ve always been a little disturbed by the fact that the owner of the computer involved gets the credit for discovery in these matters…
    I ran SETI at home for many years on my PC, not in a search for glory, but because I believe in the greater cause. I would expect no more recognition should a discovery have been made on my computer than I would expect if I had lended out my garage to someone who borrowed it and went on to win a race…
    It’s a small gripe I know, but I believe the most of the glory should go to the software engineers and theorists who designed the systems allowing this whole disseminated processing to take place.

  • wayne

    My motto is, “I’ll take 100% of the blame if things go South, but you have to give me 10% of the credit, when things go right.”

    Garry- good stuff. (you are a jack-of-all-trades! You need to be running your local School Board!)

    This is what you ran into (in part):
    P vs. NP and the Computational Complexity Zoo

  • Localfluff

    Hey, that’s my lucky number there! They found it, damn.
    With the advent of quantum computing, all current (prime-based) ciphers will be immediately cracked. There are quantum safe ciphers (I’ve heard) but even if implemented by everyone from today, the “damage” from revealing everything secret thus far is mind boggling. The next Y2K kind of stuff. 2024 is the real Y2K :-)

  • Localfluff

    Oh, 2048, so we have 30 years. No hurry.

  • wayne


    Halt and Catch Fire, Episode 1,
    “Computer’s aren’t the thing…”

  • wayne

    totally off-thread, and not to make lite of the opiate situation in your area, but this is hilarious:

    “This is Your Brain on Drugs”
    – Extended Cut, Rachael Leigh parody

  • Garry

    Wayne, that P vs. NP video had my head spinning, but I think I got the gist of it.

    The parody is pretty good; I can laugh because it doesn’t show the true signs of drug abuse I saw this summer (emaciated appearance, multiple infections, scabbed over injection sites, etc.).

  • wayne

    try this–

    I don’t mean to make lite of that tragic situation, and our original thread has been weighing on my mind more than usual lately. I’m shifting back into vocational rehab, and that will include opiate misusers.

  • Garry

    Wayne, thank you for going back into the fray.

    My neighbor has been doing much better of late; the 4th (or is it 5th?) rehab this year apparently made something click. Even better, his house has been a way station for friends who are making life changes; different people have moved in for a few weeks at a time as their leases expire but before they move. We’ve had some great dinner parties, which has kept my neighbor busy and in good spirits, while helping me get out more.

    I’ve always thought that family is truly the key to overcoming mental health issues (including substance abuse), and sometimes family takes the form of good friends.

    It must be hard to deal with these issues as part of your job; I imagine the success rate isn’t terribly high, but the successful cases must bring a great sense of satisfaction.

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