Base 20 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 67: | \[{20^{67}-1\over19}\] | 906779 × 607366391 × 141027529625834791277325880782894530434550121999834925322075700531980089<72> |