WeChat ID
aaronpk_tv
"37ab-cdefgh-ijklm
All Amex cards start with 37
ab is tied to the country of issuance/market
cd usually relates to the product in the AmEx portfolio
e is billing cycle
fghi is account number
j is the issue number
kl are position on the account, starting with 00 for the main (basic) card holder
m is the Luhn/mod 10 check digit"