how many children were separated from there parents or relatives during or after hurricane katrina

As of September 8, 2006, 1220 children were still on the Hurricane Katrina missing persons list. This includes children that are either missing or simply looking for their parents.
Over 250 children have already been successfully reunited with family members

I think the answer is near the millions?

Actually, the number of children separated from their parents or relatives during or after Hurricane Katrina is not in the millions. The accurate number is difficult to determine precisely, but according to available data, around 1,220 children were still on the missing persons list related to Hurricane Katrina as of September 8, 2006. It's important to note that this number includes both children who were missing and children who were looking for their parents. Please keep in mind that this data might have changed since then.