The work was famously described by Albert Einstein as "perhaps the greatest intellectual stride that it has ever been granted to any man to make."
Russia's Kaliningrad region has announced the castle is up for sale.
"I tried to negotiate less gray hair, and Kehinde's artistic integrity would not allow (him) to do what I asked," Barack Obama said of the portrait.
Nobilified has also done paintings involving Bruno Mars, Ellen DeGeneres and professional athletes.
Roger Stone has one too. Anyone else?
No country allows limitless "quasi-freedom" online, the Russian leader said.