TikTok is one of the hottest apps on the planet. But this is not the result of Silicon Valley twenty-somethings. TikTok is actually the mastermind of 35-year-old Zhang Yiming, who lives in China. His company, ByteDance, has seen blistering growth. In fact, according to Forbes, he is worth over $16 billion (this makes him the 13th richest person in China).