U(120847)/483389 / 13776557 / 26651135744461 / 878266627571589517816969 / 5142437846187952260620261

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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 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:	U(120847)/483389 / 13776557 / 26651135744461 / 878266627571589517816969 / 5142437846187952260620261
Verification status (*):	PRP
Official Comment (*):	Fibonacci cofactor, ECPP
Proof-code(s): (*):	E1 : Batalov, CM
Decimal Digits:	25181 (log₁₀ is 25180.275927677)
Rank (*):	75171 (digit rank is 1)
Entrance Rank (*):	75163
Currently on list? (*):	yes
Submitted:	5/29/2026 19:22:19 UTC
Last modified:	5/29/2026 19:37:14 UTC
Database id:	142283
Status Flags:	Verify
Score (*):	35.2985 (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.

Elliptic Curve Primality Proof (archivable *)
Prime on list: no, rank 83
Subcategory: "ECPP"
(archival tag id 240316, tag last modified 2026-06-01 11:37:11)
Fibonacci cofactor (archivable *)
Prime on list: yes, rank 6
Subcategory: "Fibonacci cofactor"
(archival tag id 240317, tag last modified 2026-05-29 19:37:17)

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.

field value

prime_id 142283

person_id 9

machine Using: Digital Ocean Droplet

what prp

notes PFGW Version 4.0.4.64BIT.20221214.x86_Dev [GWNUM 30.11]
Primality testing U(120847)/483389/13776557/26651135744461/8782666275...9517816969/5142437846...2260620261 [N-1/N+1, Brillhart-Lehmer-Selfridge]
trial

Running N-1 test using base 2
Generic modular reduction using generic reduction FMA3 FFT length 8K, Pass1=128, Pass2=64, clm=2 on A 83648-bit number
Running N+1 test using discriminant 11, base 1+sqrt(11)
Generic modular reduction using generic reduction FMA3 FFT length 8K, Pass1=128, Pass2=64, clm=2 on A 83648-bit number
Calling N-1 BLS with factored part 0.03% and helper 0.01% (0.11% proof)

U(120847)/483389/13776557/26651135744461/8782666275...9517816969/5142437846...2260620261 is Fermat and Lucas PRP! (45.0803s+0.0089s)
[Elapsed time: 50.00 seconds]

modified 2026-05-29 19:23:51

created 2026-05-29 19:23:01

id 188469

field	value
prime_id	142283
person_id	9
machine	Using: Digital Ocean Droplet
what	prp
notes	PFGW Version 4.0.4.64BIT.20221214.x86_Dev [GWNUM 30.11] Primality testing U(120847)/483389/13776557/26651135744461/8782666275...9517816969/5142437846...2260620261 [N-1/N+1, Brillhart-Lehmer-Selfridge] trial Running N-1 test using base 2 Generic modular reduction using generic reduction FMA3 FFT length 8K, Pass1=128, Pass2=64, clm=2 on A 83648-bit number Running N+1 test using discriminant 11, base 1+sqrt(11) Generic modular reduction using generic reduction FMA3 FFT length 8K, Pass1=128, Pass2=64, clm=2 on A 83648-bit number Calling N-1 BLS with factored part 0.03% and helper 0.01% (0.11% proof) U(120847)/483389/13776557/26651135744461/8782666275...9517816969/5142437846...2260620261 is Fermat and Lucas PRP! (45.0803s+0.0089s) [Elapsed time: 50.00 seconds]
modified	2026-05-29 19:23:51
created	2026-05-29 19:23:01
id	188469

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