There are a lot of different names involved in either residential or commercial real estate. Most of the one's you've mentioned google gives good examples on. Especially the math is fun one that popped up as you use the NPV-Net Present Value to get your IRR- the internal rate of return.
At any rate you say the purchase price is $1,600,000 for 16 units which is $1m per unit-the NOI is $181,000/12=$15,083 per month income after all expenses except these here.
The following are not operating expenses: principal and interest, capital expenditures, depreciation, income taxes, and amortization of loan points.
Generally, most loans are amortized over 30 years due in whatever terms you get so you take $1,600,000/360=$4,444+ interest, and the others mentioned above. So $15,083-$4,444=$10,639 if you qualify for a 5% interest rate that is $800,000/360=$2,222 so then you subtract that from the $10,639-$2222=$8417 per month net income before taxes or the capital expenditures, depreciation. Which with a good CPA as some that are on here advising you never know unless you ask :) depends on how much you think you need to make per month out of it...It's a close one. but it works out to about $101,004 per year but the full projection will probably be necessary. Those are just the basics to give you an idea of how to analyze a deal in my book :) Good Luck :)