Ehhhhh, sort of? But more: "surprisingly close to one day", because if you want to do correct time-keeping, a real day (or rather, a sidereal day, the time in which the earth makes one full rotation wrt "fixed" stars) is currently 86164090.7 milliseconds long.

You could also look at the solar day (the time it takes the earth to rotate such that the sun appears in the same place), in which case a day is actually a little longer than 86400000ms.