PCR processes number of amplicons produced
This is a theoretical consideration, as PCR depends on a number of factors as optimal priming, salt concentration, enzyme activity, available dNTPs and so on. Ideally the number of DNA molecules is doubled with every cycle. So the general formula to calculate the number is:

$ n \times 2^{cycles} = $ number of DNA molecules at the end of the PCR

n is the number of molecules set into the reaction

So for our 600 DNA molecules with 25 cycles this would give:

$600 \times 2^{25} = 20.132.659.200$ or roughly 20.1 billion molecules of DNA.