The advice to apply separately for a master's program is very good. If you can take the GREs (general and math subject) and do well, then many institutions will be willing to take a chance on you as a master's student. Especially if you are willing to pay your own way even for the first year, then you should not have much trouble getting accepted at a decent program.

Reputation on MO is not worthless, but it is not a commodity with any recognized exchange rate. I am on the graduate admissions committee in my department, and I can't really imagine giving any weight to MO rep specifically. It is true that I have become deeply impressed by some undergraduates via their activities on this site. But this is not by virtue of having accumulated a certain amount of reputation per se but rather because of the deep knowledge and cleverness that oozes out of every corner of their posts. Anyway, I have little doubt that these pyrotechnic undergrads need a leg up in their graduate applications: there will be ample conventional evidence of their excellence.

As for whether being an actuary will be helpful in your application: that will probably be very department-specific. As others have said, if you can find a department which has some kind of actuarial program, it is worth contacting someone in that program (even if you don't want to pursue actuarial anything as part of your PhD) because they will be able to evaluate your skills and accomplishments and, if appropriate, convey their esteem to the admissions committee. To give one data point, I believe the current admissions committee at UGA has little or no experience with actuarial science, and it would be hard for us to evaluate a candidate with that background. I have the vague impression that actuaries are smart, mathematically minded people (and wasn't one of the biggest Jeopardy winners of the classical era an actuary?), but if you told me you had passed seven out of nine actuarial exams [note: I have no idea whether there are nine actuarial exams; I just made the number up], I wouldn't know what to make of it.

Come to think of it, perhaps a letter from someone with one foot in the actuarial community and another in academic mathematics would be a good idea. She could explain and translate your accomplishment into terms we would better understand.

The advice to apply separately for a master's program is very good. If you can take the GREs (general and math subject) and do well, then many institutions will be willing to take a chance on you as a master's student. Especially if you are willing to pay your own way even for the first year, then you should not have much trouble getting accepted at a decent program.

Reputation on MO is not worthless, but it is not a commodity with any recognized exchange rate. I am on the graduate admissions committee in my department, and I can't really imagine giving any weight to MO rep specifically. It is true that I have become deeply impressed by some undergraduates via their activities on this site. But this is not by virtue of having accumulated a certain amount of reputation per se but rather because of the deep knowledge and cleverness that oozes out of every corner of their posts. Anyway, I sincerely doubt that these pyrotechnic undergrads need a leg up in their graduate applications: there will be ample conventional evidence of their excellence.

As for whether being an actuary will be helpful in your application: that will probably be very department-specific. As others have said, if you can find a department which has some kind of actuarial program, it is worth contacting someone in that program (even if you don't want to pursue actuarial anything as part of your PhD) because they will be able to evaluate your skills and accomplishments and, if appropriate, convey their esteem to the admissions committee. To give one data point, I believe the current admissions committee at UGA has little or no experience with actuarial science, and it would be hard for us to evaluate a candidate with that background. I have the vague impression that actuaries are smart, mathematically minded people (and wasn't one of the biggest Jeopardy winners of the classical era an actuary?), but if you told me you had passed seven out of nine actuarial exams [note: I have no idea whether there are nine actuarial exams; I just made the number up], I wouldn't know what to make of it.

Come to think of it, perhaps a letter from someone with one foot in the actuarial community and another in academic mathematics would be a good idea. She could explain and translate your accomplishment into terms we would better understand.