Age may be just a number, but that number matters when it comes to retiring. The common definition of early retirement is any age before 65 — that's when you may qualify for Medicare benefits. Currently, men retire at an average age of 64, while for women the average retirement age is 62.
The earliest you can get your State Pension is when you reach your State Pension age. You'll have to wait to claim your State Pension if you retire before you reach that age.
As to how many hours you can work and still collect Social Security, this will obviously depend on your hourly wage. For example, if you earn $20 per hour, you can work 1,170 hours per year before your Social Security benefits are reduced, assuming you haven't yet reached full retirement age.