What lump sum was deposited first in a bank that offers a 5% interest compounded monthly to be able to withdraw 4605 birr per month at the end of each month for 13 years?

The lump sum deposited first would be 645,890 birr. This can be calculated using the formula for present value of an annuity: PV = PMT x ((1 - (1 + i)^-n) / i), where PV is the present value, PMT is the periodic payment, i is the interest rate, and n is the number of payments. In this case, PV = 4605 x ((1 - (1 + 0.05)^-156) / 0.05) = 645,890 birr.