15 groups of order 81.
| SmallGroups | group |
|---|---|
| (81, 1) | C81 #724 |
| (81, 2) | C92 #725 |
| (81, 3) | C32⋊C9 #726 |
| (81, 4) | C9⋊C9 #727 |
| (81, 5) | C3×C27 #728 |
| (81, 6) | C27⋊C3 #729 |
| (81, 7) | AΣL(1,𝔽27) #730 |
| (81, 8) | #731 |
| (81, 9) | #732 |
| (81, 10) | #733 |
| (81, 11) | C32×C9 #734 |
| (81, 12) | C3×H(3,𝔽3) #735 |
| (81, 13) | C3×3−1+2 #736 |
| (81, 14) | #737 |
| (81, 15) | C34 #738 |