ULTRAMASSIVE BLACKHOLE

How massive is a 600 billion miles diameter ultramassive black hole? What will happen if it enters our solar system?

Our solar system would become part of its accretion disc long before it entered.

The most massive black hole known is TON-618, it's event horizon is only about 200 billion miles. Here's how our inner solar system compares

 Hypothetical black hole is 3 times this size. The idea of this thing entering our solar system is equivalent to an elephant entering a birdhouse.