By Larisha Paul BTS are back in a big way. The supergroup’s comeback album Arirang, their first full-length LP in six years, brought in record-breaking first week sales. Arirang sold 641,000 total copies in its first week of release — the most by a group since Billboard started tracking streaming numbers in 2014 — including 532,000 in pure album sales. That latter figure is the biggest by a group in over a decade, Billboard reports; it’s the most pure album sales by a group since One Direction’s Midnight Memories in 2013. Within 24 hours of arrival, Arirang racked up the most single-day streams for an album released this year on Spotify. BTS also brought in their all-time biggest streaming day on Apple Music. The numbers show that the record was worth the wait. BTS spent the past few years on hiatus as RM, Jin, Suga, J-Hope, Jimin, V, and Jung Kook completed their mandatory military service in South Korea and explored solo projects.…