Looks like the game is a great success for Atlus:
Persona 5 ships over 1.5 million worldwide just days after P5 released in the West.
http://gematsu.com/2017/04/persona-5-worldwide-shipments-top-1-5-million
Persona 5 is by far the biggest launch for the series in the UK - #1
Launched on Tuesday on PS4 and PS3 and receiving glowing reviews, ‘Persona 5’ from Atlus/Deep Silver debuts at No1. It is the first J-RPG (Japanese RPG) to debut at the top of the All Formats Chart since ‘Ni no Kuni: Wrath of the White Witch’ back in W5 2013 (‘Final Fantasy XV’ launched at No2, but it had to contend with ‘FIFA 17’). It is by far the biggest launch for a ‘Persona’ title and the first ever All Formats No1 for developer and publisher Atlus.
Japan is back, baby.
(Yakuza 0 is the best selling Yakuza in the West since the PS2 era, Nier: Automata sold over a million copies worldwide and is considered by Square as a great success, same goes for Nioh for Tecmo-Koei who seemed really chuffed reaching over a million sales worldwide too)
I just hope that Atlus take a leaf out of From Software's book and stay the same as they are, since they were attempting to chase after certain audiences a little while ago, so hopefully they keep releasing quality games. Happy for them though, they were niche, now they've pretty much reached From Software's level of popularity, I think.