$ time openssl prime "$(openssl prime -safe -generate -bits 512)"
FA9DD2ACADD2DCB625D647D2056D104C173E07AD1064B765BB67624C3368D6304E73F14B684007B14692D3B2163C3324FD7AFEEE1083B7B11D2083145A8C8083 (13125850941187027381265984532675202511130004698004280048627595209772076020458862657399397479100572349460666009458004455401529142692260342913961157116854403) is prime

real    0m0,320s
user    0m0,308s
sys     0m0,009s

for name in "${!XDG@}"; do
  declare -n var="$name"
  printf '%-25s = %s\n' "${name@Q}" "${var@Q}"
  unset -n var
done