How do you know, Khachanov is not an Armenian name.
many Armenians who live outside of homeland are modifying their names to be similar with local names
Agassian - Agassi (his father lived in Iran), Khachanian - Kchachanov (similar to Russian name ending )
in Armenian language "Khach" means "Cross", it has religian meaning...
only David's father did not make it in Latin style Nalbandino