17 921 Exponent Status

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

PrimeNet Exponent Status

M_n

Status

Details

Composite, with 6 known prime factors. Cofactor is composite.

Factored

Factor	Digits	Bits	Date
1433681	7	20.5	old
33655639	8	25.0	2008-08-26 19:58:51
34945951	8	25.1	2008-08-26 19:58:51
555359460353	12	39.0	2008-08-26 19:58:51
69216002352933895609	20	65.9	2008-10-16 23:57:27
26911328390944995598673	23	74.5	2008-10-16 23:57:27

ECM

Digits	B1	Curves
25	50000	280 / 280
30	250000	640 / 640
35	1000000	1566 / 1566
40	3000000	2724 / 4588

Estimated T-Level: 38.0 ⓘ

TF below 2^121 is very unlikely to find new factors due to ECM effort.

Status	Date	User	Residue	Number of known factors	Shift	Type	Base
Verified	2017-09-21	Oliver Kruse	C799C6AD4E26BA7F	6	0	1	3
Verified	2017-10-02	kkmrkkblmbrbk	C799C6AD4E26BA7F	6	0	1	3
Verified	2017-12-07	ATH	C799C6AD4E26BA7F	6	894	1	3
Verified	2020-04-17	Oliver Kruse	1F2D0203019C1CB7	6	12703	5	3
Verified	2024-07-01	kkmrkkblmbrbk	1F2D0203019C1CB7	6	7671	5	3

History

Date	User	Type	Result
2025-01-07	masser	NF-PP1	Start=6/5, B1=132000000, B2=131868000000
2025-01-01	masser	NF-PP1	Start=112/47, B1=132000000, B2=131868000000
2024-12-21	masser	NF-PP1	Start=2/7, B1=132000000, B2=131868000000
2024-07-01	kkmrkkblmbrbk	C-PRP	M17921/1433681/26911328390944995598673/33655639/34945951/555359460353/69216002352933895609 : 1F2D0203019C1CB7 PRP: Verified PRP without proof (small exponent)
2023-05-20	JacobZ	NF-PM1	B1=5900000000, B2=16484172846891750
2021-08-27	Seth_Tr	NF-PM1	B1=400000000
2020-04-17	Oliver Kruse	C-PRP	M17921/1433681/33655639/34945951/555359460353/69216002352933895609/26911328390944995598673 : 1F2D0203019C1CB7 PRP: Verified PRP without proof (small exponent)
2017-12-07	ATH	C-PRP	M17921/1433681/33655639/34945951/555359460353/69216002352933895609/26911328390944995598673 : C799C6AD4E26BA7F PRP: Verified PRP without proof (small exponent)
2017-10-02	kkmrkkblmbrbk	C-PRP	M17921/1433681/33655639/34945951/555359460353/69216002352933895609/26911328390944995598673 : C799C6AD4E26BA7F PRP: Verified PRP without proof (not generated)
2017-09-21	Oliver Kruse	C-PRP	M17921/1433681/33655639/34945951/555359460353/69216002352933895609/26911328390944995598673 : C799C6AD4E26BA7F PRP without proof (not generated)
2008-10-16	-Anonymous-	F-ECM	Factor: 26911328390944995598673
2008-10-16	-Anonymous-	F-ECM	Factor: 69216002352933895609
2008-08-26	-Anonymous-	F	Factor: 555359460353
2008-08-26	-Anonymous-	F	Factor: 34945951
2008-08-26	-Anonymous-	F	Factor: 33655639