Good Morning Gwen, 

Thank you for contacting the U of M Extension Service. 

Your cactus is amazing! We are volunteers who answer yard and garden questions for Minnesota. I am not familiar with dividing a cactus. 

If you would like to find a new home for it, let's consider who to contact;

Here is a link to the U of M College of Biological Science, Conservatory and Botanical Collection: https://cbs.umn.edu/conservatory

At the bottom of their website there is contact information. You might send photos of the cactus to them and ask them if they know of any local conservatory that might want it. 

There are other conservatories in the area; Minnesota Landscape Arboretum,  Como Park Conservatory and possibly the Minnesota Zoo. You might contact them to see if they know of anyone who might want it. How fun!

The U of M Conservatory and Botanical Collection might be able to give you advice on dividing it. 

Good Luck!