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<?php $number = 1234567890; $hex = strtoupper(dechex($number)); $hex_padded = str_pad($hex, 9*2, "0", STR_PAD_LEFT); preg_match_all('/.{2}/', $hex_padded, $matches); $result = array_reverse($matches[0]); var_dump($result);

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34.91 ms | 402 KiB | 5 Q