How to classify Android Devices based on DPI values?

In Android, various devices are classified into different categories based on their density.

LDPI = 120 DPI
MDPI = 160 DPI
HDPI = 240 DPI
XHDPI = 320 DPI
XXHDPI = 480 DPI
XXXHDPI = 640DPI

Here my doubt is, if an Android device has density as "200 DPI", will it falls under which of the above category? (example: Nexus 5 have 217dpi,whether it'll come under HDPI or MDPI).

Can anyone say, what is the exact range for different densities(LDPI,MDPI,XXHDPI.....).

It's not one density but rather ranges (often called "buckets"). This is documented here and this picture I post below should explain how to classify it correctly (it lacks xxhdpi and xxxhdpi though, but the rule is the same)