While some may disagree, I'd say that the handgun with the most in common with an AK-47 would be a S&W hand-ejector DA revolver. Consider the following:
-The S&W hand-ejector has been in continuous production since 1899, longer than any other handgun
-Since 1899, S&W has produced millions, if not tens of millions of hand-ejector revolvers.
-S&W hand-ejectors have influenced more DA revolvers than any other manufacturer. At least some part of the S&W design has been copied by Taurus, Rossi, Astra, Manurhin, and numerous other manufacturers.
-S&W hand-ejectors introduced many of the most popular cartirdges available including .38 Special, .357 Magnum, .44 Special, .41 Magnum, and .44 Magnum. Additionally, S&W was the first to devise a way to successfully chamber a rimless semi-auto cartridge in a DA revolver witht the M1917 in .45 ACP (Colt also made 1917's, but S&W came up with the half-moon clips).
-The S&W hand-ejector has been chambered for an extremely wide array of cartridges from .22 Long Rifle up to .44 Magnum
-S&W hand-ejectors proved themselves through two world wars and countless smaller ones (the S&W M15 remained the standard-issue sidearm of the USAF until 1985).
-S&W revolvers were popular with U.S. police for most of the 20th century (from the early 1900's until the 1980's and early 1990's) and dominated the police market from the 1950's through the 1970's.
-A S&W revolver requires only the most basic maintenance to remain reliable
-Anyone of even moderate intelligence can understand how to use a S&W revolver within a matter of seconds.
So, while other may eclipse it in the future, a very strong argument could be made that the S&W hand-ejector is the most popular handgun of all time.