As 11 and 31 are both primes, this is really asking when the year was last a prime - that was 2003. So 31/11/2003 was the last all prime date.
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If it's so worn that it has no letters or numbers it shouldn't be possible to see a date. However if the date is barely visible it may still be worth a few dollars, but it would have to be graded more exactly. 1871 three-cent nickels are moderately rare.
There are 30 days in September. 2, 3, 5, 7, 11, 13, 17, 19, 23, and 29 are prime. 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 25, 26, 27, 28 and 30 are composite. 1 is neither. The prime numbers have two factors. The composite numbers have more than two.
10
credit card numbers are the 16 digit numbers on the front of the card and the expiration date is when the card expires.
The answer depends on how the date is written: ddmmyy or ddmmyyyy or mmddyy or mmddyyyy