Congo - Brazzaville Business Directory: COG is the ISO 3 alphabet country code of Congo - Brazzaville. Currency of Congo - Brazzaville is FCFA, which has a short code of XAF. Capital of Congo - Brazzaville is Brazzaville. Congo - Brazzaville has the population of 5399895 and approximate area is 342000.00 square kilometers (or approx. 212518.8 square miles). Population density of Congo - Brazzaville is approx. 15/Km2 (or approx. 9.321/mile2)