There's no cite for the 171 million, which is a bit hard to believe. There are cites (which I didn't check) for these claims. Maybe they are counting people watching clips on Twitter?

According to Streams Charts, the ceremony peaked at 4.4 million concurrent viewers—the most in its history and a 9% increase from 2024—including 1.4 million viewers on the official YouTube broadcast (an 8% increase) and 1.8 million on Twitch. On YouTube, the ceremony peaked at 2.4 million total concurrent viewers (a 9% increase), including a record 8,600 co-streams.[6] More than 16,500 creators co-streamed on Twitch—a record for the show, representing a 50% yearly increase—with total unique viewers and hours watched each increasing 5% from 2024.[6][114] On Twitter, posts about the show increased by 12%, with more than 1.79 million posts from December 10–12, while the broadcast and related videos received over 60 million views.[6]