51989197414600215 · 267202 - 1

At this site we maintain a list of the 5000 Largest Known Primes which is updated hourly.  This list is the most important PrimePages database: 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:

Description:51989197414600215 · 267202 - 1
Verification status (*):Proven
Official Comment (*):Cunningham chain (4p+3)
Proof-code(s): (*):L6373 : Karakai, Magyar, Farkas, Jarai, LLR
Decimal Digits:20247   (log10 is 20246.533681724)
Rank (*):77288 (digit rank is 1)
Entrance Rank (*):77276
Currently on list? (*):yes
Submitted:10/12/2026 09:48:02 UTC
Last modified:10/17/2026 00:37:12 UTC
Database id:142508
Status Flags:none
Score (*):34.6242 (normalized score 0)

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.
Cunningham Chains (1st kind) (archivable class *)
Prime on list: yes, rank 1, weight 44.32376073048
Subcategory: "Cunningham chain (4p+3)"
(archival tag id 240456, tag last modified 2026-10-17 00:37:15)

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_id142508
person_id9
machineUsing: Digital Ocean Droplet
whatprime
notesCommand: /var/www/clientpool/1/pfgw64 -V -f -tp -q"51989197414600215*2^67202-1" >command_output 2>&1
PFGW Version 4.0.4.64BIT.20221214.x86_Dev [GWNUM 30.11]
Primality testing 51989197414600215*2^67202-1 [N+1, Brillhart-Lehmer-Selfridge]
trial
Running N+1 test using discriminant 13, base 1+sqrt(13)
Generic modular reduction using generic reduction FMA3 FFT length 8K, Pass1=128, Pass2=64, clm=2 on A 67260-bit number
Calling Brillhart-Lehmer-Selfridge with factored part 99.92%


51989197414600215*2^67202-1 is prime! (27.0001s+0.0001s)
[Elapsed time: 30.00 seconds]
modified2026-10-17 00:26:35
created2026-10-17 00:26:05
id188691

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