An aerosol-generating device (100) comprises a heating element (406) and an external housing (500, 502). The external housing is elongate and is adapted to resist rolling. The external housing has a transverse cross-section forming a shape having at least three corners connected by curves, in which the corners are spaced by between 2 mm and 10 mm and are connected by curves having a radius of curvature of between 100 mm and 10000 mm. An aerosol generating system comprises the aerosol-generating device and a charging device (600) having a cavity (302) configured to receive the aerosol-generating device.
