A fan having a rotor for generating a fluid flow includes a stator and a rotor, which form an electromagnetic rotary drive for rotating the rotor about an axial direction. The rotary drive is an external rotor, and the rotor includes a magnetically effective core configured in an annular manner. The impeller includes a hub on which a plurality of blades configured to generate the fluid flow is arranged, and the stator is a bearing and drive stator configured to magnetically drive the rotor without contact and magnetically levitate the rotor without contact with respect to the stator. The rotor is capable of being actively magnetically levitated in a radial plane perpendicular to the axial direction, the hub of the impeller completely enclosing the magnetically effective core of the rotor, and the stator is encapsulated in a stator housing and formed of a low-permeable material.