Determining all biunitary triperfect numbers of a certain form

Abstract

We shall show that $2160$ is the only biunitary triperfect number divisible by $27=3^3$.

arXiv comment11 pages. Some minor corrections (for example, σ^{**}(N2)/N2 > 2 should be σ^{**}(N2)/N2 > 3/2) arXiv admin note: text overlap with arXiv:1705.00189