A centrifugal compressor of an aircraft engine includes an impeller and a shroud extending circumferentially around the impeller. A bellmouth disposed upstream of the impeller extends circumferentially and includes: a conduit section extending from a first end to an upstream-most location of the bellmouth, the first end of the conduit section secured to the shroud, and a peripheral section extending from the upstream-most location to a second end located radially outwardly of the first end, the peripheral section located radially outwardly of the conduit section and axially overlapping the conduit section. A stiffening member is located on the peripheral section of the bellmouth proximate the second end. The stiffening member extends circumferentially and provides the bellmouth with a dynamic vibration mode outside a range of dynamic vibration modes of the aircraft engine during operation.