  We study the motion of electrically charged particles, magnetic monopoles,
and magnetic dipoles around electrically and magnetically charged stringy black
holes. From the analysis of the radius of the innermost stable circular orbit
(ISCO) of electrically charged particles, we show that the electric charge $Q$
of stringy black holes can mimic well the spin of Kerr black holes; the black
hole magnetic charge $Q_m$ can mimic spins up to $a_* \simeq 0.85$ for magnetic
dipoles; the magnetic charge parameter $g$ of a magnetic monopole can mimic
spins up to $a_* \simeq 0.8$. This is due to the destructive character of the
magnetic field and such a result excludes the existence of an appreciable black
hole magnetic charge in astrophysical black holes from the observation of
rapidly rotating objects with dimensionless spin up to $a_* \simeq 0.99$. We
then consider the magnetar SGR (PSR) J1745-2900 as a magnetic dipole orbiting
the supermassive black hole Sagittarius A* (Sgr A*). We show that Sgr A* may be
interpreted as a stringy black hole with magnetic charge $Q_{\rm m}/M \leq
0.4118$.
