The brain is the most complex machine in the universe. It has over 100,000,000, 000 nerve cells each with up to 150,000 connections. Each cell is connected to 25,000 others.

The human brain contains approximately 86 billion neurons, not 100 billion as stated. However, the general scale is correct - each neuron can have thousands of synaptic connections (up to 10,000 or more), creating an incredibly complex neural network. The brain's complexity in terms of interconnectivity is indeed unparalleled in the known universe.