13 721 Exponent Status

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

PrimeNet Exponent Status

M_n

Details

Composite, with 1 known prime factor. Cofactor is composite.

Trial Factored to 2⁶⁸

TF target 2⁴⁴

Factored

Factor	Digits	Bits	Date
2281528776694793	16	51.0	old

ECM

Digits	B1	Curves
25	50000	280 / 280
30	250000	640 / 640
35	1000000	1566 / 1566
40	3000000	4588 / 4588
45	11000000	1546 / 9201

Estimated T-Level: 40.8 ⓘ

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
Verified	No proof (small exponent)	2017-09-21	Oliver Kruse	5B8418BC58EAE239	1	0	1	3
Verified	No proof (small exponent)	2017-10-12	kkmrkkblmbrbk	5B8418BC58EAE239	1	5382	1	3
Verified	No proof (small exponent)	2020-04-17	Oliver Kruse	0BBE91EE53415E2B	1	585	5	3
Verified	No proof (small exponent)	2024-07-01	kkmrkkblmbrbk	0BBE91EE53415E2B	1	13000	5	3

History

Date	User	Type	Result
2025-02-23	masser	NF-PP1	Start=195/59, B1=430000000, B2=429570000000
2025-02-11	masser	NF-PP1	Start=2/7, B1=430000000, B2=429570000000
2025-01-25	masser	NF-PP1	Start=6/5, B1=430000000, B2=429570000000
2024-07-01	kkmrkkblmbrbk	C-PRP	M13721/2281528776694793 : 0BBE91EE53415E2B
2024-01-29	-anonymous-	NF-PM1	B1=100000000000, B2=122154521813133810
2023-05-20	JacobZ	NF-PM1	B1=8000000000, B2=35524619698317750
2022-03-04	Ethan O'Connor	NF-PM1	B1=1000000000, B2=248016220902450
2022-02-06	ANONYMOUS	NF-PM1	B1=50000
2020-04-17	Oliver Kruse	C-PRP	M13721/2281528776694793 : 0BBE91EE53415E2B
2017-10-12	kkmrkkblmbrbk	C-PRP	M13721/2281528776694793 : 5B8418BC58EAE239
2017-09-21	Oliver Kruse	C-PRP	M13721/2281528776694793 : 5B8418BC58EAE239
2017-09-21	Oliver Kruse	C-PRP	M13721/2281528776694793 : 5B8418BC58EAE239