There are some letters from Charles Babbage in the James Paget collection (which is kind of weird: it’s an autograph collection, so in many cases it’s literally a matter of lists of signatures–like a list of members of a philosophical club–but in other cases there are letters that are, now, interesting for reasons beyond the simple signature). In a 2 June 1870 letter to Mrs. Paget, Babbage discussed a “very successful experiment” involving his Analytical Engine. It added a 26 digit number and a 25 digit number in under 30 seconds.
Just a fun fact to whip out at a party. (Assuming, of course, that you go to the good sort of party, where Charles Babbage Facts are appreciated.)