Is the Alien number written in the I-797 approval notice of I-730 form?

Now I'm in U.S and when I went to issue social security card, I've been informed that the A-number is not written on I-94 form in my passport. So, I have to wait till I got the employment authorization card which has the Alien number.But now I almost completed 21 days and i got nothing but I saw the I-797 approval notice and I found 9 digit number started with "A" under my name and my wife's name.