Which Manufacturer has a Laps of 21, a Grid larger than 16, and a Rider of akira ryō?
CREATE TABLE "moto_gp_classification" (
  "rider" text,
  "manufacturer" text,
  "laps" real,
  "time_retired" text,
  "grid" real
);
SELECT "manufacturer" FROM "moto_gp_classification" WHERE "laps"=21 AND "grid">16 AND "rider"='akira ryō';