The 4 groups don't have a meaning. They do, actually. First digit is 4 for VISA, 5 for

**Mastercard**, 6 for**Discover**/**Diners Club**, 3 for**American Express**/**Diners Club**(those are shorter than 16). Also, first 6 digits for Visa and**Mastercard**are code numbers for the issuing institution.Besides, what is the number of Visa card?

1 (800) 847-2911

Are all credit card numbers 16 digits?

Take a look at your

**card**and count the**digits**. You'll most likely discover that if you have an American Express, your**card**has 15**digits**. Discover and Mastercard keep their accounts at**16 digits**, and although most Visa**cards**are**16 digits**, some can have as many as 19.What kind of credit card starts with a 4?

Credit card numbers are created in a consistent way.

**American Express**cards start with either 34 or 37.**Mastercard**numbers begin with 51–55.**Visa cards**start with 4.