How to return the content of cell 1 in cell 3 if content in cell 2 is looked up?

my problem is as follows:
I have a set of data with headings in row 1, say A1:P1.
I then have numbers in row 2, A2:P2.
What formula should I enter in another cell, say Z1, that look up a specific number in A2:P2, and if the cell containing the number is A2, then Z1 will return the heading in A1?

Many thanks

in AA1 you can place =indirect(char(64+match(z1,"a2:p2",0))&"1"). In Z1 you will enter the desired number so I chose AA1 to display the result

thanks for the reply
I entered the number in A2 into Z1 and =indirect(char(64+match(z1,a2:p2,0))&"1") without "" around a2:p2 in AA1 as excel says there is error.
The outcome is 0 instead of the A1 heading in AA1.
By the way can I ask what does the 64 imply?

Wow, thanks Ace_XL, it works perfectly!