That’s what analysts call a tough compare.

Nobody expects a repeat of that kind of surprise in two weeks when the company reports its first quarter earnings for fiscal 2013. Breakneck growth like that just can’t go on forever — especially with Samsung flooding the market with cheaper knock-off Androids.

Also, Q1 2012 had an extra week — 14 rather than the usual 13 — a fact I fully expect many reporters to forget when they do their year-over-year growth calculations this time around.

Still, as the two tall bars in the chart above suggest, the 57 analysts we’ve heard from so far — 33 professionals and 24 independents — expect that Apple managed to ship a ton of iPhones in the quarter that ended Dec. 29.

The high estimate of 63 million — from congenitally bullish independent Nicolae Mihalache — represents 84% growth year over year (adjusted for the short quarter). Topeka Capital’s Brian White, despite his Street-high $1,111 price target, has come in with the lowest estimate of all: 43 million, up only 26% (adjusted) above last year.

You’re probably safer betting on a number closer to the median: 49.5 million, up 45% from last year (or 34% if you forget to take last year’s extra week into account).

We’ll find out which of our analysts was closest to the mark when Apple reports its earnings after the markets close on Wednesday Jan. 23. I’ll be on an island in the Gulf of Thailand that day, but will file my Earnings Smackdown report as soon as I get back to dry land.

Below: The analysts’ individual estimates, with the pros in blue and the amateurs in green.