you can search both in Google, they are the "hitmakers" for pop singers.
Martin Sandberg known professionally as Max Martin, is a Swedish songwriter, record producer and singer. He rose to prominence in the second half of the 1990s after making a string of major hits such as Britney Spears's "...Baby One More Time" (1998), The Backstreet Boys's "I Want It That Way" (1999) and Bon Jovi's "It's My Life" (2000).
Martin has written or co-written 22 Billboard Hot 100 number-one hits, most of which he has also produced or co-produced, including Katy Perry's "I Kissed a Girl" (2008), Maroon 5's "One More Night" (2012), Taylor Swift's "Blank Space" (2014), and The Weeknd's "Can't Feel My Face" (2015). Martin is the songwriter with the third-most number-one singles on the chart, behind only Paul McCartney (32) and John Lennon (26). In addition, he has had the second most Hot 100 number-one singles as a producer, 20, behind George Martin, who had achieved 23 by the time of his death.
In early 2013, his single sales were tallied by The Hollywood Reporter to be at over 135 million. According to Variety, his net worth was approximately $260 million in 2017. The previous year he achieved approximately an income of $54 million and a profit of $19 million for his services.