First after applying I was sent an email with a link to a fifty-question assessment to take. This assessment included questions on math, vocabulary, and pattern-finding.
Based on the results from that, the recruiter scheduled a brief interview over the phone (this took roughly fifteen minutes). At the end of this, the recruiter scheduled an in-person interview.
The in-person interview was fairly rigorous. I had to take a similar fifty-question assessment (to demonstrate that I had not cheated on the first one, I think). I then met with two teams of two interviewers, both of which talked to me for about an hours each.