81,815 is an arithmetic, composite, deficient, evil, odd, semiprime, and square-free number. It is an 8,183-gonal number. It is the short leg of a Pythagorean triple: 81,815^2 + 133,873,872^2 = 133,873,897^2.
A mathematician was working on a difficult problem for an engineer at the sewage treatment plant.
He called up the engineer and and told him the solution was 288.
This solution did not sound right to the engineer, so he asked the mathematician to explain how he arrived at this particular answer.
"Just can't do that. It's just too gross!"