I read an article from twenty THIRTEEN saying, as of then, bitcoin had more power than the top 500 supercomputers. At that time, the difficulty was 21.3 million. Now, it is almost 11 trillion and projected to pass that number within September 2019. So, using that info, the computer says that the network uses 350,000 times as much (SHA256 brute forcing) computational power as those computers did. Is that still true and if so, what is the number of times more powerful now?
bitcoin had more power than the top 500 supercomputers
This is a nonsensical comparison.
Sure, nothing compares to the aggregate of all Bitcoin miners in quickly computing the last 32 bits of the double-SHA256 hash of particularly structured 80-byte inputs.
But at the same time, Bitcoin mining hardware can also literally not do anything else. It can't even multiply two numbers.
You simply cannot compare specialized Bitcoin hashing hardware with general-purpose supercomputers. Each is designed for a certain goal, and very good at that goal.
Is bitcoin the most powerful computer network in the world?
If you're going to define network so abstractly, I'm sure that the Internet has a lot more computational power connected to it.
The hashrate of the bitcoin network is currently estimated to be ~80,000,000 TerraHashes/sec. In Sep 2013, the hashrate of the bitcoin network was estimated to be ~600 TerraHashes/sec. That's a 133,000-fold increase.