This question is more difficult to answer than one might think, there is no signal definition and any attempt is liable to criticism for whom it includes and whom it leaves out.
Matters are only complicated by the fact that the term Muslim world is often used interchangeable with the Middle East and Horn Africa, when only quarter of the world Muslims live in this region.
One simple definition is the membership of the organization of the Islamic conference (OIC), an assembly of states with significant Muslim population which defines itself as the collective voice of the Muslim world, the OIC members are a diverse grouping, spanning four continents and 57countries. Though this definition of the Muslim world excludes Muslim minorities living in other countries like the Muslims in India and Ethiopia and includes non Muslim populations in OIC member countries.
Using OIC definition, the 57 countries that constitute the Muslim world contain 1.5 billion people, it means one quarter of the world population, Muslim countries mostly are poor countries living standers are often low and many families face hardship one in four people countries live extreme poverty people aged 15 and above are mostly illiterate, 25 of the 57 are classified as low income countries by world bank.
As a group the Muslim world is young of its 1.5 billion people, the majority is under the age of 24.
Many of the worlds security hotspots are in the muslim world , two in three muslim countries are currently in conflict or face a significant threat of conflict, compared to only one in four non muslim countries, Somalia, Afghanistan, Syria are the most high profile countries grappling with instability and conflict.
By Mohamed Farah Shabelle