Iran (/ɪˈrɑːn/ or /aɪˈræn/; Persian: ایران [ʔiːˈɾɒn] ( )), also known as Persia (/ˈpɜrʒə/ or /ˈpɜrʃə/), officially the Islamic Republic of Iran, is a country in Western Asia. It is bordered on the north by Turkmenistan, with Kazakhstan and Russia across the Caspian Sea; on the east by Afghanistan and Pakistan; on the south by the Persian Gulf and the Gulf of Oman; on the west by Iraq; and on the northwest by Armenia, Azerbaijan and Turkey. Comprising a land area of 1,648,195 km2 (636,372 sq mi), it is the second-largest nation in the Middle East and the 18th-largest in the world; with over 77 million inhabitants, Iran is the world's 17th most populous nation. It is the only country that has both a Caspian Sea and Indian Ocean coastline. Iran has been of geostrategic importance because of its central location in Eurasia and Western Asia and the Strait of Hormuz.