In Russia, Kazakhstan and Belarus
Russia
The account number has 20 digits. The first five show whose account it is: 40817 — an individual, 40802 — a sole proprietor (ИП), 40702 — a commercial organization. Digits 6–8 are the currency code (810 — rubles).
Kazakhstan
In Kazakhstan, the account number is called ИИК and is written in IBAN format: 20 characters, starting with KZ.
Belarus
In Belarus, the number of a current (settlement) account is written in IBAN format: 28 characters, starting with BY.