According to Metcalfe's Law the price of Bitcoin should be in the region of $5,000 – $8,000 per coin.
If you want to know how exactly this is calculated, you can see it here:
http://www.renegadeinvestor.co.uk/bitcoin/is-the-price-of-bitcoin-undervalued-by-several-thousand-dollars/
The exact user numbers are not known. I tried ago justifying user numbers by official statistics like currently logged in users at Poloniex and similar. Not every node on the network represents a real user. Most transactions are spam to clog the mempool. Trade sites might act dishonest on their stated user numbers, to attract new investors.
That erroneous input goes wrong exponential (n2) so Metcalfe's output runs even more errant. Oh, and he never meant his calculation beeing economically focused, instead observed communication network's usefullness.