It is not the cube root Zac, it is the 4th root.
$$2^{1/4}=\sqrt[4]{2}$$
$${{\mathtt{2}}}^{\left({\frac{{\mathtt{1}}}{{\mathtt{4}}}}\right)} = {\mathtt{1.189\: \!207\: \!115\: \!002\: \!721\: \!1}}$$
It is an irrational number so this is an approximation :)