It is not uncommon that, when I am going through the process of signing someone up for the Old Navy credit card, we will get to the step where they are entering their social security number and they will pause and say, "Oh...I don't know it."
I would just like to take this moment to say: If you are old enough to apply for a credit card, you are old enough to know your social security number by heart.
I memorized my social security number when I started applying for jobs at around age 16, because you have to put it on every application.
But if you are one of those privileged children who doesn't need a job, you should definitely have your social security number memorized when you start applying for college and all the applications ask for it.
And if that doesn't apply either, you just memorize it at some point anyway!
They ask for it at doctors' offices, for goodness' sake! And you know when else they ask for it? When you apply for credit cards. So get your social security number memorized if you want a card. Thanks.