The number is over double the 1 million downloads Microsoft saw for the IE9 Beta and four times that of the IE9 RC over the same time period. That's not too surprising: more people will download the final version than the unfinished versions.
The above video shows the launch of Microsoft's latest browser, along with various demos of what it can do. If you haven't seen it yet, it's worth a look.
2.35 million is a decent number for 24 hours, but it is hardly impressive. The current record holder is still Mozilla, which had over 8 million downloads of Firefox 3 in a 24-hour period on June 18, 2008. Did you contribute to Microsoft's number?