16804 is the decimal notation for the octal number 40644. Check 2nd example of the PHP manual for the meaning of these values.
40644
extracted:
4
- the file is a directory
0
- padding to get the first 4
on the 5th position
6
- read-writable for the owner
4
- readable only for the group
4
- readable only for the world.
PHP recognizes numbers with a leading zero as an octal number. If you need to convert a string containing 0755
or 755
to a decimal number, use octdec()
. The reverse function (decimal to octal) is decoct()
.
If you need to change the file permissions of a file, use chmod()
. For that to work, you need to be the owner of the file, otherwise you get a Permission denied error.