The function GIphi returns the number of Gaussian integers in a reduced system modulo n.

A system of Gaussian integers incongruent each to each with respect to a given modulus n is called a reduced system of incongruent numbers modulo n.

$\mathrm{with}\left(\mathrm{GaussInt}\right)\:$

$\mathrm{GIphi}\left(-201-43\mathrm{I}\right)$

$15600$