Six degrees of separation between us and everyone else on this planet. The President of the United States, a gondolier in Venice, just fill in the names. I find it A) extremely comforting that we're so close, and B) like Chinese water torture that we're so close because you have to find the right six people to make the right connection...
7.5 Billion (2017) The current world population is 7.5 billion as of March 2017 according to the most recent United Nations estimates elaborated by Worldometers. The term World Population refers to the human population (the total number of humans currently living) of the world.
86 for a man and 100 for a woman. Well, according to the CIA's The World Factbook, the current average human lifespan is approximately 66 and a half years. On average the current life expectancy for the world is about 67.2 years. (see the first related link).