On some of their addresses they have a wallet number assigned, what does it mean?

https://bitinfocharts.com/bitcoin/address/12ib7dApVFvg82TXKycWBNpN8kFyiAN1dr

Here is said wallet 967? What does the number 967 mean?

Or here they have another number 559

https://bitinfocharts.com/bitcoin/address/15Z5YJaaNSxeynvr6uW6jQZLwq3n1Hu6RX

Thanks