Into how many parts does the LCC divide the whole knowledge?

The Library of Congress Classification (LCC) system divides knowledge into 21 main classes, which are further divided into subclasses. The main classes are:

1. General works
2. Philosophy, psychology, religion
3. Social sciences
4. Language and literature
5. Science
6. Technology
7. Arts and recreation
8. Literature
9. History and geography
10. Education
11. Law
12. Military science
13. Political science
14. Economics
15. Commerce
16. Public administration
17. Social and public welfare
18. Medicine
19. Engineering
20. Music
21. Fine arts

Within each main class, there are many subclasses that allow for more specific organization and classification of materials. The LCC system is used by many libraries around the world, particularly in the United States, to organize and classify their materials in a way that makes it easy for patrons to find what they are looking for.