$url = 'https://www.instagram.com/instagram/';
$curl = curl_init();
$options = [
CURLOPT_URL => $url,
CURLOPT_RETURNTRANSFER => true,
CURLOPT_SSL_VERIFYPEER => false,
CURLOPT_CONNECTTIMEOUT => 20,
CURLOPT_TIMEOUT => 20,
CURLOPT_USERAGENT => 'Mozilla/5.0 (Windows NT 6.3; WOW64; rv:49.0) Gecko/20100101 Firefox/49.0',
CURLOPT_REFERER => 'https://www.instagram.com/',
];
curl_setopt_array($curl, $options);
$html = curl_exec($curl);
curl_close($curl);
preg_match('@\".*_followed_by\":\s+{\s+\".*":\s([\d]{4})\s+}@',$html, $finded);
$followers = $finded[1];
echo 'result: '.$followers;