How much DNA molecules are in a PCR

Size of diploid human genome: 2 x 3 billion bp = 6 billion bp
Average size of of nucleotides:  487 + 159 g/mol = 646 g/mol
Single cell DNA amount: 6 billion * 646 g/mol = 3.87 pg
In 25 ng PCR human genomic DNA : 25000 pg / 3.87 pg = 6459 copies