https://serverfault.com/questions/734615/lastlogon-vs-lastlogontimestamp-in-active-directory

The LastLogonTimeStamp Attribute – What it was designed for and how it works

https://blogs.technet.microsoft.com/askds/2009/04/15/the-lastlogontimestamp-attribute-what-it-was-designed-for-and-how-it-works/