Base 2 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 447: | \[2^{447}-1\] | 7 × 86656268566282183151<20> × 8235109336690846723986161<25> × 72751284869088788795301631728906362894695299875729701287430721838248329952225963533888951<89> |