To answer your first question about the length... The value of the cell is
still 1234, so the LEN function will return 4. If you want the LEN to
include the zeros you will need something like LEN(TEXT(A1,"00000000000")).
If you plan on using other text functions, you will need to change them like
this as well.

As for your second question I made the same format and it stayed as custom.
It doesn't really matter as long as the cell looks and acts the way you want.

"GARY" wrote:

A cell contains 1234.

I then format the cell by doing /FORMAT/CELLS/NUMBER/CUSTOM with "type"
= 00000000000 and I press OK. The cell's contents is displayed
00000001234.

However, the length of the cell is only 4 characters (not 11) and its
format has changed from "Custom" to "Special".

How do I keep the "Custom" formatting?