As part of the demotion process from planet to dwarf planet, to maintain consistency Pluto was stripped of its name and given a number like all other non-planetary objects in the solar system. Pluto was reclassified and renamed with the designation 134340. The decision was made to reinforce Pluto’s demotion - every asteroid in our solar system is given a number, so the same process was taken to officially ‘dwarf’ the former planet.

More Info: