Australia is 3.6 times larger than Saudi Arabia.
Area: 7,741,220 km2 World Factbook
Population: 22,507,617 (July 2014) World Factbook
Australia, officially the Commonwealth of Australia, is a country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. It is the world's sixth-largest country by total area. Wikipedia
Area: 2,149,690 km2 World Factbook
Population: 27,345,986 (July 2014) World Factbook
Saudi Arabia, officially known as the Kingdom of Saudi Arabia, is the largest Arab state in Western Asia by land area and the second-largest in the Arab world after Algeria. Wikipedia