I think this will come as a surprise to most people. 2.2 sounds like it's above the replacement rate, but as Jesús Fernández-Villaverde explains, selective gendered abortions & high infant mortality in some countries mean that it isn't.
The figures for South Korea are quite stark. They've engineered a society where they'll shrink to 20 million in size from today's 51 million. His figures rely on the average human life expectancy staying at 85. It's possible in decades to come that may exceed 100. It may not, but there are lots of people working to make it happen.