<?php

    $t = gmp_init("229478441072721921");
    $byte_array_t = gmp_export($t, 8);
    $base64 = base64_encode($byte_array_t);
 
    echo $base64;
    
    
    $decode = base64_decode($base64);
    $import = gmp_import($decode, 8);
    $int = gmp_intval($import);
    
    echo $int;