https://www.cnbc.com/2018/11/09/why-we-will-never-run-out-of-16-digit-credit-and-debit-card-numbers.html

Americans have, on average, more than three credit cards each. Many also have debit cards, flexible spending cards and other accounts that are all associated with a unique 16-digit number that enables transactions.

Plus, most popular virtual payment methods now use so-called tokenization, which means that there are additional unique numbers tied to your account. Each card you have loaded into Apple Pay, for example, is tying up three 16-digit combinations, since the watch and phone each use a unique tokenized number.