Most estimates put the worldwide figure at roughly 450,000, not even half a million.
Hey Fred,
Not quibbling over figures, but this page says the UN estimated in 2012 that there were about 316,600 centenarians alive. But, 450,000 or 317,000, either way, a very interesting point made on the page was the estimate that only 1 in a thousand make it to age 110 (super centenarian). So, of the 450,000 or 317,000 centenarians in 2012, there will only be between 450 to 317 alive by 2022.
Here we are more than 5 years after 2012. The numbers must be markedly lower by now.