Aims. We study the link between gravitational slopes and surface morphology on the nucleus of comet 67P/Churyumov-Gerasimenko and provide constraints on the mechanical properties of the cometary material (tensile, shear and compressive strengths). Methods. We computed the gravitational slopes for five regions on the nucleus, representative of the different morphologies observed on the surface (Imhotep, Ash, Seth, Hathor and Agilkia), using two shape models computed from OSIRIS images by the stereo-photoclinometry (SPC) and stereo-photogrammetry (SPG) techniques. We estimated the tensile strength, shear strength and compressive strength using different surface morphologies (overhangs, collapsed structures, boulders, cliffs, Philae’s footprint) and mechanical considerations. Results. The different regions show a similar general pattern in terms of relationship between gravitational slopes and terrain morphology: i) low slopes terrains (0 – 20°) are covered by a fine material and contain a few large (>10 m) and isolated boulders, ii) intermediate slope terrains (20 – 45°) are mainly fallen consolidated materials and debris fields, with numerous intermediate size boulders from