Simple math:

Let's call, for simplification, the smallest denomination of Electroneum/ETN (which is 0.01 ETN) "microETN".

The smallest denomination of Bitcoin is Satoshi (0.00000001 BTC).

Now the math:

The total amount of Sathoshi it will be: 2,100,000,000,000,000 (2,100 bln).
The total amount of "microETN" it will be: 2,100,000,000,000,000 (2,100 bln) - so the same.

The only problem is that now a Satoshi is only @ $0.00007 and "microETN" is @ $0.0003.

The total amount of BTC at today's price is "worthing": 21,000,000,000 * 7,444 = $156,324,000,000,000
The total amount of ETN at today's price is "worthing": 21,000,000,000,000 * 0.03 = $630,000,000,000,000 - about 4 times more than BTC.

How much the market cap for ETN needs to be to sustain this price?

You draw the conclusion...

(English is not my native language so I apologize for the eventual mistakes)