File: symfony\symfony\src\Symfony\Component\Serializer\Encoder\XmlEncoder.php
Method: parseXmlAttributes
Code:

        foreach ($node->attributes as $attr) {
            if (ctype_digit($attr->nodeValue)) {
                $data['@'.$attr->nodeName] = (int) $attr->nodeValue;
            } else {
                $data['@'.$attr->nodeName] = $attr->nodeValue;
            }
        }

If attribute value > "2147483647" then result value exact 2147483647

For example, if the value of the attribute is "8834232342323423423", then the value will be 2147483647.