If you've heard of a CEO, there's a good chance that you have heard of the Chief Financial Officer (CFO) OR Chief Financial and Operating Officer (CFOO). Sometimes this person is referred to as the “numbers” person because they oversee financial activities for the company.
According to Investopedia:
The CFO is the senior manager who is responsible for overseeing the financial activities of an entire company. This includes signing checks, monitoring cash flow and financial planning.
According to Business Dictionary:
Senior-most executive responsible for financial control and planning of a firm or project. He or she is in charge of all accounting functions including (1) credit control, (2) preparing budgets and financial statements, (3) coordinating financing and fund raising, (4) monitoring expenditure and liquidity, (5) managing investment and taxation issues, (6) reporting financial performance to the board, and (7) providing timely financial data to the CEO. Also called chief finance officer, comptroller, controller, or finance controller.