# Credit card virtual number

• Dec 4th 2008, 04:31 AM
fractal
Credit card virtual number
The other day, my brother & I were online shopping and to pay the merchant, we used a credit card virtual number from our credit card company website. It's mastercard virtual number cc generator if you're curious. Anyways, how many unique, non-identical, 16-digit number from 0 to 9 that can be generated? I wonder how long because it would run out of number, similarly with phone number in the US where it is just 10-digit. Thanks, newbie
• Dec 4th 2008, 06:55 AM
tester85
If you are only talking about digits for the credit card virtual number then it should be 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 = 10 ^ 16

Quote:

Originally Posted by fractal
The other day, my brother & I were online shopping and to pay the merchant, we used a credit card virtual number from our credit card company website. It's mastercard virtual number cc generator if you're curious. Anyways, how many unique, non-identical, 16-digit number from 0 to 9 that can be generated? I wonder how long because it would run out of number, similarly with phone number in the US where it is just 10-digit. Thanks, newbie

• Dec 4th 2008, 08:19 AM
fractal
3!
@tester85: Are you saying that there can be a maximum of 10^16 credit card number that exists with the mastercard 16-digit? I'll try to clarify here. So there are 16 place holder, where each one can be occupied by any number from 0 to 9. how many combination can be made? For example, ABC can be sorted six times without repetition. ABC ACB BAC BCA CAB CBA which is like 3!=6. Is there something similar for the credit card question. Thanks.
• Dec 7th 2008, 11:26 PM
repcvt
Quote:

Originally Posted by tester85
If you are only talking about digits for the credit card virtual number then it should be 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 = 10 ^ 16

Agree it. In fact ,i know mastercard cann't be some digital on some position.For example ,i just saw first number of MasterCard is 5 .