Membership Numbers Question

Hi, I am sorry if this is the completely wrong place to ask this but I couldn't think of another place that might know. I was wondering if anyone had any insight into how to read a membership number. It is clearly not just the number of the person who was baptized in order. So how is it broken down? Thanks

These pages might be helpful:
Membership Record Number Ending in “A”
Membership record number (note that this page hasn't been updated since 2013)

Thank you so much for directing me to this, it’s a bit more complicated than I was expecting! It is however helpful to read a little bit of the history of when they started keeping record and reaching 10 million etc. Thanks again.