a phrasal verb hard to understand

[xiaoerlang]

Right now Im an International Business Major and I can tell off the top of my head the reason that I chose this was because I wanted to work for the Travel Channel and get paid to travel. However I dont want major in broadcast at all. I go to Mizzou which has the #1 Journalism school in the nation..but for seem reason the program doesnt rub me that right why.

what's the meaning of off the top of my head?
does #1 means first?

i'll appreciate your help,waiting for your response.

[dariomatty]

Well first of all "off the top of my head" is not a phrasal verb; rather, it would be a locution. At first glance I would say that it purports to be an emphatic way of saying " I can absolutely say that ... " I can definitely affirm that... ".
This is just the way I perceive that proposition. But I am not entirely sure.
I never used it before. it seems really colourful.

[BobK]

It usually means 'without preparation':

Q: What are our sales figures for last quarter?
A: I don't know off the top of my head, but I'll find out and let you know before the meeting on Friday.

b

[Barb_D]

Mizzou is the University of Missouri. When the various universities that offer degrees in journalism are ranked based on the strength of their program, Missouri is first. It is the #1 school of journalism in the country. (At least, this is what the author if this passage has written.)

(I have two siblings who graduated from that program. Neither is in journalism at this point, although my sister did do broadcast journalism for a while.)

{not a teacher, but the sister of two Missouri alums}