No you would have to set the info to a variable for that. So...
integer iListen0;
// this will be a reference to your listener.
// You do not need the reference, but it's a good idea to get used to using them.
// if you wish to remove the listener, which is a sim friendly practice,
// you would say llListenRemove(iListen0);
integer iChannel = 0;
// channel you want to listen on, 0 is regular chat
// you may listen on, and submit commands on, non visual channels
// by using the form "/channelnumber command" (without the quotes)
// i.e., /7 50 would say "50" on channel 7, and nobody would see it.
integer iKeepNumber;
// this variable will be used to store your incoming number
// so that your program remembers it and can use it
// anywhere in the script.
default
{
state_entry()
{
iListen0 = llListen(iChannel, "", llGetOwner(), ""

;
// iListen0 is now a reference to this specific listener
}
listen(integer chnl, string s, key id, string m)
{
iKeepNumber = (integer)m
// this turns the incoming text message into a number
// and stores it in the iKeepNumber variable.
// until you clear the variable or the script crashes.
llSay(0, "I am at " + m + " meters"

;
// m is the incoming message.
// if the owner of the object says "50", the obect will say, "I am at 50 meters"
llListenRemove(iListen0);
// the object will now stop listening until the script is reset
// or until you create a new listener.
// leave this out if you want the object to keep on listening.
}
}
This is a VERY basic example, and overlooks some best practices for the sake of simplicity. For instance, you would want to know something about floats vs. integers, casting (i.e. changing "strings", that is, text, into numbers, or numbers into strings) and how to validate an incoming command to ensure it is indeed a number.
For instance, you can not llSay(0, "I am at " + iKeepNumber + " meters"

, because llSay does not know how to "say" a number, it only knows how to say strings. You would have to "cast" (change) into a string, like this...
llSay(0, "I am at " + (string)iKeepNumber + " meters"

;
Keep in mind this does not change the original variable, it only interprets it into a string for this use. iKeepNumber is still an integer.
To keep the code short, you can remove all lines that start with "//". Those are comments and have nothing to do with the running code.
If you want more help look me up in game I actually hate posting code on the forums. However, if you can get this working, the Wiki might make more sense.
Good luck.