Short answer - 180. Longer answer:
Since 1983, I've administered four different IQ tests to clients, updating to newer versions when they were published. These tests have used three different cutoff points for "genius" (two had the same cutoff) and these were 130, 150, and 180.
I've been given IQ tests myself at age 5, a few years later (can't recall what grade I was in), college, and as a working adult. The first one I scored 135 without attempting the last page, because when I asked what the test was for, for about the third time, the teacher said it was not important - I just stopped doing something I felt was useless. LOL The second test, I remember only a couple questions that angered me as a child because I thought they were tricks. Can't remember the score. Later I scored a 180 and a 160. On pop psychology IQ tests online I often score 10 or more points lower.
In an advanced psych college class, mostly white, we were given an IQ test that used African American slang as the language overall. I scored only a 35 (third highest out of 150 people) and the highest was only about 70. That was a lesson for us all.
Higher IQ is supposed to help lifetime earnings increase, but it did not apparently help mine.
I never considered testing for MENSA and the higher-level groups that require sky-high IQs, because I thought it was all too expensive - and I'm still the child that is angry at the trick question. I'm burned out on tests. LOL
A woman with a 200 (at least) IQ appeared on the David Letterman show once. She thought the show and having her on it because of IQ were all nonsense. She was not a happy person at all and extremely rude overall. I wonder if she could hold a job?
I think a better measure of intelligence is dropping a person into another culture that is pretty different and seeing how they fare.