On Sep 28, 2011, I wrote:
2*10^n (two zillion) +2*10^63 (two vigintillion) +2*10^36 (two undecillion) +2*10^12 (two trillion) +2000 (two thousand) +200 (two hundred) +20 (twenty) +3 (three)
n = {77, 113, 116, 158, 342, 464, 468, 565, 2171, 2274, 2340, 3347, 5724, ...}
The original assertion of 'two vigintillion, two undecillion, two trillion, two thousand, two hundred, ninety-three' being the alphabetically-last prime is apparently from Don Knuth & Allan Miller: A Programming and Problem-Solving Seminar, page 12 (page 20 of the ftp- available pdf < ftp://reports.stanford.edu/pub/cstr/reports/cs/tr/81/863/CS-TR-81-863.pdf
), June 1981 (the solution dating to October 1980). Chapter 1 of the seminar (Alphabetized Integers) provides a good background discussion, contextualizing the problem.
I have one more zillionized, alphabetically-last-prime candidate after n = 5724: n = 39960.