  Among a dozen known magnetar candidates there are no binary objects. As an
estimate of a fraction of binary neutron stars is about 10% it is reasonable to
address the question of solitarity of magnetars, to estimate theoretically the
fraction of binary objects among them, and to mark o probable companions. We
present population synthesis calculations of binary systems. Our goal is to
estimate the number of neutron stars originated from progenitors with enhanced
rotation, as such compact objects can be expected to have large magnetic
fields, ie. they can be magnetars. The fraction of such neutron stars in our
calculations is about 13-16%. Most of these objects are isolated due to
coalescences of components prior to a neutron star formation, or due to a
system disruption after a supernova explosion. The fraction of such neutron
stars in survived binaries is about 1% or lower. Their most numerous companions
are black holes.
