concatenation of cells to equal length

hi,
the data in the excel sheet is
1
456
69023456
12
1556
1890765
1234567890
12345
178902345
111111
12345678

Now this data may be even more jumbled in the files that i work on
can you suggest a formulae to make the lenght of this cells=10 by appending zeros before the number
Ex:1 should change to '0000000001
and 1234567890 should remain as it is (as its length is already 10)

Try:

=TEXT(A1,REPT(0,10))

copied down

replacing A1 with actual first cell to change.

If you're planning on continuing to use them as numbers in calculations, then another option is to format the cell (Numbers> custom), enter 0000000000 Otherwise, NBVC's formula is the best (I've always used =REPT(0,10-LEN(A1))&A1, his is way better).