Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 92: | \[{21^{92}-1\over20}\] | 22 × 11 × 13 × 17 × 47 × 277 × 461 × 599 × 691 × 19597 × 477045301 × 11918195405621<14> × 2215825387044753577<19> × 139870566115103282847737<24> × 2641770975903509717963660601029203121<37> |