242643801 - 1
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At this site we maintain a list of the 5000 Largest Known Primes which is updated hourly. This list is the most important databases at The Prime Pages: a collection of research, records and results all about prime numbers. This page summarizes our information about one of these primes.

This prime's information:

field (help)value
Description:242643801 - 1
Verification status (*):External
Official Comment:Mersenne 46??
Unofficial Comments:This prime has 1 user comment below.
Proof-code(s): (*):G12 : Strindmo, GIMPS, Prime95
Decimal Digits:12837064   (log10 is 12837063.2301257)
Rank (*):3 (digit rank is 1)
Entrance Rank (*):2
Currently on list? (*):short
Submitted:6/13/2009 12:36:33 CDT
Last modified:6/13/2009 12:48:13 CDT
Database id:88847
Status Flags:none
Score (*):54.4506 (normalized score 55524.0729)

Archival tags:

There are certain forms classed as archivable: these prime may (at times) remain on this list even if they do not make the Top 5000 proper.  Such primes are tracked with archival tags.
Mersenne (archivable *)
Prime on list: yes, rank 3
Subcategory: "Mersenne"
(archival tag id 210459, tag last modified 2013-02-05 07:54:28)

User comments about this prime (disclaimer):

User comments are allowed to convey mathematical information about this number, how it was proven prime.... See our guidelines and restrictions.

Great Internet Mersenne Prime Search by Woltman & Kurowski writes (11 Sep 2014): 

On April 12th, the 47th known Mersenne prime, 242,643,801-1, a 12,837,064 digit number was found by Odd Magnar Strindmo from Melhus, Norway! This prime is the second largest known prime number, a "mere" 141,125 digits smaller than the Mersenne prime found last August.

Odd is an IT professional whose computers have been working with GIMPS since 1996 testing over 1400 candidates. This calculation took 29 days on a 3.0 GHz Intel Core2 processor.

The prime was independently verified June 12th by Tony Reix of Bull SAS in Grenoble, France using the Glucas program running on Bull NovaScale HPC servers, one featuring Itanium2 CPUs and another featuring Nehalem EX CPUs.

Perfectly Scientific, Dr. Crandall's company which developed the FFT algorithm used by GIMPS, makes souvenir posters you can order. You'll need a good magnifying glass to read all 12.8 million digits!

Verification data:

The Top 5000 Primes is a list for proven primes only. In order to maintain the integrity of this list, we seek to verify the primality of all submissions.  We are currently unable to check all proofs (ECPP, KP, ...), but we will at least trial divide and PRP check every entry before it is included in the list.
fieldvalue
prime_id88847
person_id9
machineRedHat P4 P4
whattrial_divided
notesCommand: /home/caldwell/client/TrialDiv/TrialDiv -q 1 2 42643801 -1 2>&1
[Elapsed time: 12.306 seconds]
modified2011-12-27 16:48:43
created2009-06-13 12:48:01
id107060

fieldvalue
prime_id88847
person_id9
machineExternal
whatprime
notesThe prime was independently verified June 12th by Tony Reix of Bull SAS in Grenoble, France using the Glucas program running on Bull NovaScale HPC servers, one featuring Itanium2 CPUs and another featuring Nehalem EX CPUs.
modified2009-06-13 13:15:55
created2009-06-13 12:38:02
id107059

Query times: 0.0002 seconds to select prime, 0.0003 seconds to seek comments.