A rotor of a turbomachine compressor, including a bladed rotor disk fitted at its radially external end with a wall forming the inner end of an annual flow channel of a primary gas flow, and formed from multiple angular sectors, each of which is delimited between two blades of the disk which are consecutive in a circumferential direction and includes a bulging portion which is convex in the axial direction and in the circumferential direction, together with, upstream from the bulging portion, a troughed portion which is concave in the axial direction and in the circumferential direction and which has a base which is roughly punctiform.