Von Numers was a founding member of the Finnish Heraldic Society and its first chairman (1957 – 1964), as well as a member of the International Heraldic Academy (Académie Internationale d'Héraldique) from its founding in 1949.
Von Numers var en af grundlæggerne af Finsk Heraldisk Forening og dens første formand (1957-1964), ligesom han var medlem af det Internationale Heraldik Akademi (Académie Internationale d'Héraldique) fra dets grundlæggelse i 1949.