Mathematics GRE

Nowadays, many graduate schools are asking about what other places you are applying to. Moreover, I read on Quora that it is better to only write the names of graduate schools that are somewhat similar to the one you are applying to. So, I am applying to following universities to pursue a PhD in Analytic Number Theory:

1. Ohio State University
2. University of Minnesota
3. Texas A&M University
4. University of Virginia
5. Washington State University
6. University of Texas at Dallas

As I am an international student, I was wondering if the first 4 schools are perceived as "similar" graduate schools by other math students and the universities themselves?

Yes, they are quite similar, with most candidates likely having relative preferences in the same order.

I'm uniquely qualified to speak on this as I completed undergrad at the #1 school on your list and am currently pursuing my PhD at the #2. I can say pretty confidently that both of those schools are structurally similar.

#3 is fairly similar as well, though slightly below them in ranking. As for #4, I don't know much about them but I've heard their department is on the smaller end. (Still decent, just smaller)

OSU, UMN, & TAMU are very much big departments.