In Scrum, the Product Owner is 1 of 3 roles in the Scrum Team along with the Scrum Master and Developers. The Product Owner is responsible for Product Strategy, Vision and representing the customer. They need to be a mix of business strategist, entrepreneur, visionary, marketer, product designer, plus manage customers, stakeholders and other attributes.
The Product Owner day is not typical. Every day is different as products are developed and released. However, updating the Product Backlog should feature every day, and might take up to 10-15% of your day. Scrum Events will feature prominently as well.