The Hwasong-13,
AKA NATO designated KN-08 is composed of nine parts.

Nuclear warhead is 3m length

A single Maneuvering rocket engine

High-speed Reentry vehicle

Post-booster vehicle, the all directional control rocket increasing significantly the accuracy is 0.5m in length

Adaptor section 0.7m length

Second stage coupling section length is 0.7m

Second solid fuel propellant stage length is 4.5m

First stage coupling section length is 1.3m

First solid fuel propellant stage length is 7m

The total lenght is about 20.7m