How to Compute the Mass of a Singularity Point?

Considering the Black Hole's singularity that occurs for r $=$ 0, representing, according to the relativists, an infinitely dense point-mass that is at the center of the Black Hole. It is not clear how to compute the mass of this singularity, since Mass $=$ Volume x Density $=$ 0 x $\infty $ $=$ 0, $\infty $, or another value? Another uncertainty arises when calculating particular cases of what relativists considers as Schwarzschild radius of a Black Hole, or the radius of the event horizon. What about a cosmic body whose escape speed would be greater than the speed of sound (instead of the speed of light)? Therefore, no sound would come out from that body, so it would be labeled as ``mute body''!