Wincalc for Windows 95/98/ME/2K/XP/Vista (201K) (20 Nov 06)

Click the above link to download the program.

Wincalc allows the user to calculate integers with millions of digits.

Some gigantic Mersenne primes have already been calculated for you. (20 Nov 06)

There are a few additional large strings of digits here. (2 Aug 06)

If the program behaves strangely, there is a page of FAQ, which may help. If not, you can e-mail me at the address found in the program’s Help|About dialog box.
Follow the links for more information about the Windows 95/98/ME/2K/XP/Vista version or the Windows 3.1 version.
19 Nov 2006: Discovered how to word-wrap my help texts. I await news of unintended consequences.
2 Aug 2006: Taught the parser to ignore non-digits when pasting a numerical text in from the clipboard.
10 Jan 2006: As expected, the 43rd Mersenne prime M30402457 took almost two days to calculate.
8 Jan 2006: I was horrified to discover, as I began the long calculation of the recently announced 43rd Mersenne prime, that the last few million digits of my version of the 42nd Mersenne prime were incorrect! (It seems that I forgot that it is necessary to add back the 1 when converting a Mersenne prime back to a power of 2; I also forgot to check my work.) The current version of M25964951 has been recalculated and checked. I hope to have M30402457 ready in a couple of days.
28 Dec 2005: In response to users reporting difficulty opening files by double-clicking file icons, new versions have been prepared that deal with file-naming conventions that allow spaces (and extra periods). See the FAQ.
2 Mar 2005: The largest known Mersenne primes are now available for downloading as Wincalc files.
14 Feb 2005: Saving a multi-page number as a text file is now done automatically, instead of requiring a page-by-page approach (a vestige of Windows 3.1 limitations).
31 Jan 2005: Minor corrections: The text windows (help files, notebooks, tables, etc) were losing their carets (the blinking thing) now and then, and were not opening files correctly.
15 Jan 2005: It seems that the old “search” function that I installed years ago in text windows no longer works under Windows XP, so I had to revise it.
23 Feb 2004: At long last, I have finished a new version of Wincalc. I await suggestions and reports of bugs.