You can also use base45 [1]: -4J5BJ+%F$C881NIMV-IG2.C (base45, 132 bits in QR) JWM9GFVXFN0RKDH4Z4KR3RV6A0 (base32, 143 bits in QR) 2009242071943347348154

You can also use base45 [1]: -4J5BJ+%F$C881NIMV-IG2.C (base45, 132 bits in QR) JWM9GFVXFN0RKDH4Z4KR3RV6A0 (base32, 143 bits in QR) 200924207194334734815443970355691218512 (decimal, 130 bits in QR) It will make use of all allowed characters in the alphanumeric mode, while being significantly shorter than base32 and as dense as decimal. And decimal encoding in general needs bignum, because there is no suitable 10^k which is only slightly larger than powers of two so no convenient binary-to-decimal encoding exists (conversely, QR code itself does make use of the fact 2^10 is only slightly larger than 10^3 for this mode). Base45 always works on three-byte groups and maintains the similar efficiency in comparison. [1] https://datatracker.ietf.org/doc/html/rfc9285 https://datatracker.ietf.org/doc/html/rfc9285