5 281 Exponent Status

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

PrimeNet Exponent Status

M_n

Details

Composite, with 3 known prime factors. Cofactor is composite.

Trial Factored to 2⁶⁸

TF target 2⁴⁴

Factored

Factor	Digits	Bits	Date
24715081	8	24.6	old
47822455589950576433	20	65.4	old
15568335055145840288561	23	73.7	old

ECM

Digits	B1	Curves
25	50000	280 / 280
30	250000	640 / 640
35	1000000	1566 / 1566
40	3000000	4588 / 4588
45	11000000	9201 / 9201
50	44000000	13380 / 16550

Estimated T-Level: 49.0 ⓘ

TF below 2^158 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	6E82628555E42FDC	3	0	1	3
Verified	No proof (small exponent)	2017-10-02	kkmrkkblmbrbk	6E82628555E42FDC	3	0	1	3
Verified	No proof (small exponent)	2017-12-07	ATH	6E82628555E42FDC	3	3483	1	3
Verified	No proof (small exponent)	2020-04-17	Oliver Kruse	05F225EB245A3ED6	3	4957	5	3
Verified	No proof (small exponent)	2024-02-03	Wentao Huang	05F225EB245A3ED6	3	4389	5	3

History

Date	User	Type	Result
2025-04-29	masser	NF-PP1	Start=98/71, B1=2100000000, B2=2097900000000
2024-02-03	Wentao Huang	C-PRP	M5281/24715081/47822455589950576433/15568335055145840288561 : 05F225EB245A3ED6
2023-06-30	-anonymous-	NF-PM1	B1=59000000000, B2=241667483419362000
2022-01-24	Ethan O'Connor	NF-PM1	B1=1300000000
2021-12-16	ANONYMOUS	NF-PM1	B1=100000000
2021-12-16	Oliver Kruse	NF-PM1	B1=1000000000, B2=1002849399191640
2020-04-17	Oliver Kruse	C-PRP	M5281/24715081/47822455589950576433/15568335055145840288561 : 05F225EB245A3ED6
2017-12-07	ATH	C-PRP	M5281/24715081/47822455589950576433/15568335055145840288561 : 6E82628555E42FDC
2017-10-02	kkmrkkblmbrbk	C-PRP	M5281/24715081/47822455589950576433/15568335055145840288561 : 6E82628555E42FDC
2017-09-21	Oliver Kruse	C-PRP	M5281/known_factors : 6E82628555E42FDC