12 781 Exponent Status

Great Internet Mersenne Prime Search
GIMPS
Finding World Record Primes Since 1996

PrimeNet Exponent Status

M_n

Details

Composite: 3 known prime factors

Trial Factored to 2⁶⁸

TF target 2⁴⁴

Factored

Factor	Digits	Bits	Date
1226977	7	20.2	old
766246513	9	29.5	2008-08-26 19:58:38
39381281878555629070620681181457046537601	41	134.9	2026-01-13 11:36:20

ECM

Digits	B1	Curves
25	50000	280 / 280
30	250000	640 / 640
35	1000000	1566 / 1566
40	3000000	4588 / 4588
45	11000000	1590 / 9201

Estimated T-Level: 40.9 ⓘ

TF below 2^131 is very unlikely to find new factors due to ECM effort.

Status	Proof	Date	User	Residue	Number of known factors	Shift	Type	Base
Factored	No proof (small exponent)	2017-09-21	Oliver Kruse	911DA5C77F0ECAE1	2	0	1	3
Factored	No proof (small exponent)	2017-10-12	kkmrkkblmbrbk	911DA5C77F0ECAE1	2	6735	1	3
Factored	No proof (small exponent)	2020-04-17	Oliver Kruse	7FDD8B82153B2EBE	2	1565	5	3
Factored	No proof (small exponent)	2024-07-01	kkmrkkblmbrbk	7FDD8B82153B2EBE	2	9672	5	3

History

Date	User	Type	Result
2026-01-13	Ryan Propper	F-ECM	Factor: 39381281878555629070620681181457046537601
2025-03-05	masser	NF-PP1	Start=94/31, B1=430000000, B2=429570000000
2025-02-20	masser	NF-PP1	Start=6/5, B1=430000000, B2=429570000000
2025-01-17	masser	NF-PP1	Start=2/7, B1=430000000, B2=429570000000
2024-07-01	kkmrkkblmbrbk	C-PRP	M12781/1226977/766246513 : 7FDD8B82153B2EBE
2023-05-27	Anton Repko	NF-PM1	B1=100000000000, B2=120417199046794650
2023-05-14	JacobZ	NF-PM1	B1=8700000000, B2=36024966470342850
2022-02-05	Joss	NF-PM1	B1=1000000, B2=3910366209750
2020-04-17	Oliver Kruse	C-PRP	M12781/1226977/766246513 : 7FDD8B82153B2EBE
2017-10-12	kkmrkkblmbrbk	C-PRP	M12781/1226977/766246513 : 911DA5C77F0ECAE1
2017-09-21	Oliver Kruse	C-PRP	M12781/1226977/766246513 : 911DA5C77F0ECAE1
2017-09-21	Oliver Kruse	C-PRP	M12781/1226977/766246513 : 911DA5C77F0ECAE1
2008-08-26	-anonymous-	F	Factor: 766246513