Two Greek numbers get confused constantly. For a remote property purchase, only one of them matters.
The AFM is the tax registration number that unlocks a purchase, a bank account and a Golden Visa file. The AMKA is the social-insurance number — important if you live and work in Greece, but largely irrelevant to a one-off transaction from abroad.
For a buyer who never plans to relocate, the AFM is usually the only number on the list. The AMKA can wait until, and if, an investment turns into time genuinely spent in the country.