What is the weight of GRE analytical-writing scores on math graduate-program admissions?
I think the entire GRE General carries very little weight overall in admissions nowadays, except for the caveat that extremely poor scores might hurt you, because it betrays a fundamental weakness in the application (usually that language skills aren’t up to par). But language abilities if you’re an international student are usually judged using the IELTS or TOEFL, so it wouldn’t likely matter unless the school imposes a floor on the Analytical Writing score.

In STEM fields in general, including math, I can’t really think of a scenario where a strong writing score will bump a candidate from rejection to acceptance in isolation.