It seems adult human being have about 1,00,000 to 1,50,000 follicles of hair (strands) on the scalp, the top of our head. There are 1 million follicles on the head including those on the scalp. These follicles are all formed when fetus is developing inside the womb of mother.
The total number actually depends on the genes and hereditary factors. Follicle is the living portion of hair under the skin and inside the body.
The maximum number of hairs is 5 million on the entire body. These follicles are also formed during the fetus stage itself. No new follicle can develop. There are millions of sweat and tubular glands on our body at the openings of hairs.