According to a BBC world population website when I was born, way back in 1972, I was (approximately) the 3,809,358,681st person alive on Earth.
I am sobered by the fact that most of the people I work with are in the four billions.
Just for completeness, the Lovely Melanie was 4,000,688,532nd, Millie 6,506,378,185th and Amber 6,709,452,950th.