EXCLUSIVE

The answer to that $53 million question -- how the hell is Kanye West that deep in debt -- is that he isn't, but he does spend a ton ... on himself.

Sources connected to Kanye tell TMZ the number -- $53 mil -- reflects how much dough 'Ye has invested in his own companies related to fashion and music. For instance, we're told he's sunk $40 million alone into 3 seasons worth of Yeezy fashion!

Yeezy shoes are all the rage now, but we're told Kanye didn't get a dime from Nike when he created the first gen of the shoe. He funded the design out of his own pocket.

Additionally, we're told he spent several hundred thousands to build sets for his last tour, and to make his 2012 short film, "Cruel Summer."

The good news for Kanye is he'll make back his investment because he earns like crazy -- $22 million in 2015 and $30 million in 2014, according to Forbes.