The long nonsense word that Peter Sellers says during his scene is actually the name of a Welsh town, known for being the longest place name anywhere: Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch.
Joan Collins was given the female lead in this final "Road" picture and Dorothy Lamour was given a small cameo appearance. When Lamour balked (and since financial backing hinged on her participation in the project), her role was enlarged.
Bob Hope's and Bing Crosby's final Road movie. Two years after Crosby's death, Hope announced the possibility (in earnest) of doing "The Road to the Fountain of Youth" with George Burns, but nothing came of it.
This Spy spoof movie, was released months before the successful James Bond film Dr. No. and two years before Carry On Spying, a black and white British comedy film that spoofed the James Bond film series. Also years after two actors who made a cameo appearance in this film (Peter Sellers and David Niven) starred in a James Bond spoof, Casino Royale while Walter Gotell eventually became involved in the James Bond franchise during the 70s and 80s as General Gogol, the head of the KGB.
The plot of this movie involving espionage and an evil organization planing to destroy world order eventually became a common plot used in spy and spy-spoof movies which proliferated years later during that decade. This trend started after the success of the very first James Bond film, Dr. No which was released months after this film.
The automatic banana-feeding machine intended for monkey astronauts seems to be inspired by - or cribbed from - the assembly line worker feeding machine that tortured poor Charlie Chaplin with buttered corn and hot soup in Modern Times (1936) - right down to the (eventually dangerous) mouth wiping function.