Definition:Divisor Count Function/Also known as

Divisor Count Function: Also known as
Some sources refer to this as the divisor function and denote it $\map d n$.

However, as this function is an instance of a more general definition of the divisor function, the more precise name divisor count function is preferred.

It is also often referred to as the $\tau$ (tau) function, but there are a number of functions with such a name.

Some sources use $\nu$, but again, that also has multiple uses.

Hence the unwieldy, but practical, divisor count function, which is non-standard.