How do I convert from this weird Coordinate unit to LngLat for use in Google Maps? -

I have a database filled with rows if such coordinates are added:

ux: 6643641 < Br> Uy: 264274
uz: NULL

I have been assigned all these coordinates to appear as interest points on Google Maps, but no one can tell me that they who were they.

What do I need for Google Maps Longitude and speed coordinates? I know that one can be changed in another, but nothing else.

I know that this is not the right place to ask about coordination systems, but I honestly can not think of any other place question.

Thanks for any help!

This is my worst, now I think there is more data for each line:

CoordSystemNumber: 23
CoordSystemName: EUREF89 UTM Sone 33

I think the format is called UTM. You need to know the zone and the hemisphere to complete the conversion. is. Is there other data related to this?

Braz