| 1373881 | Composite, with 1 known prime factor. Cofactor is composite. Trial Factored to 272 TF target 260 |
| Factored | |
| ECM | | Digits | B1 | Curves |
|---|
| 25 | 50000 | 280 / 280 | | 30 | 250000 | 105 / 640 |
Estimated T-Level: 25.8 ⓘ TF below 2^81 is very unlikely to find new factors due to ECM effort. |
| LL | | Status | Date | User | Residue | Shift | Software |
|---|
| Bad | | Alex and Nick Myrman | 53E7812CABE4575C | 0 | Nick Myrman,DWT,(aka N2) | | Factored | | Cornelius Caesar | D3E7812BABE44F5B | 0 | Mac,John Sweeney,vLL1.0b1,(aka J4) | | Bad | 1997-12-30 | Mikko Tommila | 3F7DBFA82522697C | 0 | Windows,Prime95,v13,(aka WP1) | | Factored | 2015-03-27 | NR | D3E7812BABE44F5B | 500679 | Windows 64-bit,Prime95,v28.5,build 2 | | Factored | 2015-03-27 | MadPoo 🙂 | D3E7812BABE44F5B | 186219 | Windows 64-bit,Prime95,v26,(aka We4) |
|
| PRP | | Status | Proof | Date | User | Residue | Shift | Type | Base |
|---|
| Factored | Certified Good Power=6 | 2025-09-01 | Kriesel | 88B24C62A21D3C6F | 0 | 1 | 3 |
|
| PRP Cofactor | | Status | Proof | Date | User | Residue | Number of
known factors | Shift | Type | Base |
|---|
| Verified | PRP without proof (not generated) | 2017-09-30 | Oliver Kruse | 6997999E3C3CEC54 | 1 | 0 | 1 | 3 | | Verified | PRP without proof (not generated) | 2017-10-25 | kkmrkkblmbrbk | 6997999E3C3CEC54 | 1 | 127586 | 1 | 3 |
|
| History | | Date | User | Type | Result |
|---|
| 2025-09-03 | Carlos Pinho | CERT | Proof certified good | | 2025-09-01 | Kriesel | C-PRP | 88B24C62A21D3C6F Proof Certified Good
Proof Power: 6
| | 2017-10-25 | kkmrkkblmbrbk | C-PRP | M1373881/39615513750093690993572647 : 6997999E3C3CEC54 | | 2017-09-30 | Oliver Kruse | C-PRP | M1373881/39615513750093690993572647 : 6997999E3C3CEC54 | | 2016-04-05 | BloodIce | F-ECM | Factor: 39615513750093690993572647 | | 2016-02-23 | Mark Rose | NF | no factor TF: 58-60 | | 2015-03-31 | -anonymous- | NF | no factor TF: 71-72 | | 2015-03-31 | -anonymous- | NF | no factor TF: 70-71 | | 2015-03-31 | -anonymous- | NF | no factor TF: 69-70 | | 2015-03-31 | -anonymous- | NF | no factor TF: 68-69 | | 2015-03-31 | -anonymous- | NF | no factor TF: 67-68 | | 2015-03-31 | -anonymous- | NF | no factor TF: 66-67 | | 2015-03-31 | -anonymous- | NF | no factor TF: 65-66 | | 2015-03-31 | -anonymous- | NF | no factor TF: 64-65 | | 2015-03-31 | -anonymous- | NF | no factor TF: 63-64 | | 2015-03-27 | MadPoo 🙂 | C-LL | D3E7812BABE44F5B | | 2015-03-27 | NR | C-LL | D3E7812BABE44F5B | | 2014-09-07 | mikr | NF-PM1 | B1=3106900, B2=111849000, E=12 | | 2014-04-21 | Joss | NF-PM1 | B1=200000 | | 2014-04-15 | -anonymous- | NF-PM1 | B1=145000 | | 2013-01-23 | dbaugh | NF | no factor TF: 62-63 | | 2012-08-10 | Sebastian Hornbostel | NF | no factor TF: 61-62 | | 2009-02-24 | Sturle Sunde | NF | no factor TF: 60-61 | | 2003-07-06 | -anonymous- | NF | no factor TF: 1-58 | | 2001-11-03 | -anonymous- | NF | no factor TF: 1-57 | | 1997-12-30 | -anonymous- | C-LL | 3F7DBFA82522697C | | 1997-12-30 | -anonymous- | NF | no factor TF: 1-56 |
|
