Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 84: | \[{21^{84}-1\over20}\] | 22 × 11 × 13 × 17 × 29 × 43 × 61 × 337 × 421 × 463 × 631 × 3181 × 3319 × 3697 × 4789 × 6427 × 18481 × 81867661 × 227633407 × 68454248717<11> × 22864311556633<14> × 2934413293238858072198024161<28> |