Here it is a simple (and a bit hacky, I know) one-liner for bash shell (even under Windows if you are using Cygwin) to convert the cryptic pwdLastSet timestamp of Active Directory (which represent when a user has changed the last time his/her AD password)
D=128457325992343750; date -d "01/01/1601 UTC $(let D=D/10000000; echo $D) seconds"
where the very large number after the first D= it’s your pwdLastSet value. This strange timestamp it’s a 1/100 of a nanosecond (so, it’s 1/10^7 seconds) and the ticks are counted from January 1st, 1601. Don’t ask me why, probably they didn’t like the Epoch time :)