The only one in the top 20 who is there despite doing absolutely nothing in the last couple of months (other than being awesome and a queen and a mom and wife-ish and all that)
All the others have been sweating releasing new songs or performing in one way or another (concerts, TV shows... etc)
Reigning when others work to get a spot in the top 20! She's coming for that number 1 when she releases her lead single
It happened to Rihanna's about a year ago. At one point she had caught up with Katy's followers and was about 200,000 behind. Now she is over 11 million behind.
It must be about paid followers. Because so many are fake.