Complex sentence: Mendes achieved his second No.1 at 18 years, two months and seven days old, becoming the fifth artist to score their first two No.1 albums at such a young age, following Justin Bieber, Miley Cyrus, Hilary Duff and LeAnn Rimes.
Split into simpler sentences: Mendes achieved his second No.1 at 18 years, two months and seven days old. Mendes himself, Justin Bieber, Miley Cyrus, Hilary Duff and LeAnn Rimes.