[thezilch]

In other words,

  ((16.8 + 16.8) * 1e6) * (2^15 + 2^14 - 1)) / (24 * 60 * 60)

or

  ((IANA + RIR address) * millions) * (registerable port range)) / (day-seconds)

or

  19 million scans / second