So today is an international prime day because
291113
112913
20131129
are all primes<p>Today could also have been a "perfect prime day" if MM, DD, YY and YYYY had been prime (in addition to the above). But it's not the case...<p>11 -> is prime<p>29 -> is prime<p>13 -> is prime<p>2013 -> not prime (3 x 11 x 61)<p>Too bad! We will have to wait another 16 years before we have a perfect prime day...