2 · 191287901 + 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:2 · 191287901 + 1
Verification status (*):Proven
Official Comment (*):Divides Phi(191^287901,2)
Unofficial Comments:This prime has 1 user comment below.
Proof-code(s): (*):g424 : Broadhurst, NewPGen, OpenPFGW, Proth.exe
Decimal Digits:656713   (log10 is 656712.08849398)
Rank (*):4643 (digit rank is 1)
Entrance Rank (*):370
Currently on list? (*):yes
Submitted:1/30/2015 16:36:27 UTC
Last modified:5/20/2023 20:59:19 UTC
Database id:119169
Status Flags:none
Score (*):45.3423 (normalized score 1.2391)

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.
Divides Phi (archivable *)
Prime on list: yes, rank 16
Subcategory: "Divides Phi"
(archival tag id 217894, tag last modified 2023-03-11 15:53:59)

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.

David Broadhurst writes (30 Jan 2015):  (report abuse)
Found by OpenPFGW. The order of 2 modulo this prime was confirmed by Serge Batalov's program sllr64_DivPhi.

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_id119169
person_id9
machineUsing: Xeon 4c+4c 3.5GHz
whatprime
notesCommand: /home/caldwell/client/pfgw/pfgw64 -t -q"2*191^287901+1" 2>&1 PFGW Version 3.7.7.64BIT.20130722.x86_Dev [GWNUM 27.11] Primality testing 2*191^287901+1 [N-1, Brillhart-Lehmer-Selfridge] Running N-1 test using base 5 Calling Brillhart-Lehmer-Selfridge with factored part 100.00% 2*191^287901+1 is prime! (1959.5768s+0.0209s) [Elapsed time: 32.65 minutes]
modified2020-07-07 22:30:17
created2015-01-30 16:41:02
id164774

Query times: 0.0002 seconds to select prime, 0.0003 seconds to seek comments.
Printed from the PrimePages <t5k.org> © Reginald McLean.