<P> Adherents of Islam constitute the world's second largest religious group . According to a study in 2015, Islam has 1.8 billion adherents, making up about 24% of the world population . Most Muslims are either of two denominations: Sunni (80 - 90%, roughly 1.5 billion people) or Shia (10--20%, roughly 170 - 340 million people). Islam is the dominant religion in the Central Asia, Indonesia, Middle East, South Asia, North Africa, the Sahel and some other parts of Asia . </P> <P> Around 31% of all Muslims are of South Asian origin (Pakistan, Bangladesh, Afghanistan and India combined). The Indian subcontinent as a whole, therefore, hosts the largest population of Muslims in the world . Within this region, however, Muslims are second in numbers to Hindus, as Muslims are a majority in Pakistan and Bangladesh, but not India . </P> <P> The country with the single largest population of Muslims is Indonesia in Southeast Asia, which on its own hosts 13% of the world's Muslims . Together, the Muslims in the countries of the Malay Archipelago (which includes Brunei, Singapore, Malaysia, Indonesia, the Philippines and East Timor) constitute the world's second or third largest population of Muslims . Here Muslims are majorities in each country other than Singapore, the Philippines, and East Timor . </P> <P> The various Hamito - Semitic (including Arab, Berber), Turkic, and Iranic countries of the greater Middle East - North Africa (MENA) region, where Islam is the dominant religion in all countries other than Israel, hosts 23% of world Muslims . </P>

Which country has the highest number of muslim