I am the official currency of a nation that is home to the world's largest active volcano. I am also used in a few other smaller territories within the same geographic region. The design on my banknotes often features images of significant historical figures and cultural landmarks of this country.

1. My value is determined by a managed float exchange rate.
2. My subdivisions are known as 'sen'.
3. My country is a major exporter of natural resources, particularly metals.
4. One of my banknotes features an image of a former president who was also a renowned writer.