What is a 64-bit integer?

What is a 64-bit integer?

A 64-bit integer is a 8 Byte integer.

$$\small{\text{$ \begin{array}{|r|r|r|} \hline 64\rm{Bit} & \mathrm{min} & \mathrm{max}\\ \hline \mathrm{signed} & -9,223,372,036,854,775,808 & 9,223,372,036,854,775,807 \\ \hline \mathrm{unsigned} & 0 & 18,446,744,073,709,551,615 \\ \hline \end{array} $}}$$

What is a 64-bit integer?

I'm not sure but:

Positive integers up to         $${{\mathtt{2}}}^{{\mathtt{64}}}{\mathtt{\,-\,}}{\mathtt{1}} = {\mathtt{18\,446\,744\,073\,709\,551\,615}}$$        

can be represented with 64bits