I need to pay 620 Serbian Dinars to "budget account No. 840-742221843-57, model number 97, reference number 59-013"
What is the IBAN of this account?
Wikipedia states that the Serbian IBAN format is:
RSkk bbbc cccc cccc cccc xx
Wikipedia states that
bbb is always
35, but other sites make it clear that
kk is always 35 for Serbia.
bbb is a bank code.
xx is calculated from the rest of the IBAN. The 13
c elements are for the bank account number.
You need more information than what you have available to determine the IBAN:
Your best bet is to request the IBAN from the bank or have the recipient request it for you.