PHP check folder permissions for owner/group/world

where $folder is your folder path,

echo substr(sprintf('%o', fileperms($folder)), -4);

For example to check if your folder has read-write-execute permission for owner and group, and read only for world, you could do:

if (substr(sprintf('%o', fileperms($folder)), -4) == "0774") {
      $dir_writable =  true;
} else {
      $dir_writable = false;
}

Of course, you can change the octal value to 0664 or whatever suites your need or permission need to be given for owner/group/world.