what it call a wealthy powerful businessperson

It could be a tycoon.

or an entrepreneur

A wealthy and powerful businessperson is commonly referred to as a "tycoon" or a "magnate." These terms are used to describe individuals who have accumulated significant wealth and wield considerable influence in the business world. However, it's important to note that these terms are often subjective and can vary based on context. For instance, a "real estate tycoon" refers specifically to someone who has achieved great success and wealth in the real estate industry. Similarly, a "media magnate" would denote someone who has vast control and influence over media organizations.