Mongolia is 5.1 times larger than Oman.
Area: 1,564,116 km2 World Factbook
Population: 2,953,190 (July 2014) World Factbook
Mongolia is a landlocked country in east-central Asia. It is bordered by Russia to the north and China to the south, east and west. Ulaanbaatar, the capital and also the largest city, is home to about 45% of the population. Mongolia's political system is a parliamentary republic. Wikipedia
Area: 309,500 km2 World Factbook
Population: 3,219,775 (July 2014) World Factbook
Oman, officially called the Sultanate of Oman, is an Arab state in southwest Asia on the southeast coast of the Arabian Peninsula. It has a strategically important position at the mouth of the Persian Gulf. Wikipedia