Каквото остане делиш на дни, часове и т.н.788 400/(7*24*60*60) = 1 седмица и нещо.
<?php
function duration($secs)
{
$vals = array('w' => (int) ($secs / 86400 / 7),
'd' => $secs / 86400 % 7,
'h' => $secs / 3600 % 24,
'm' => $secs / 60 % 60,
's' => $secs % 60);
$ret = array();
$added = false;
foreach ($vals as $k => $v) {
if ($v > 0 || $added) {
$added = true;
$ret[] = $v . $k;
}
}
return join(' ', $ret);
}
echo duration(788976);
?>