Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 164: | \[{21^{164}-1\over20}\] | 22 × 11 × 13 × 17 × 83 × 1231 × 1766117 × 14122861 × 83218931 × 17222085343<11> × 153065748541<12> × 914531249431<12> × 52899783148909<14> × 166149756476309<15> × 294168762061816395873078148041249581<36> × 33985282117517881270903492784746835442538163<44> × 799071455809679496983356625426375581688059909<45> |