So I was trying to calculate what the time dilation of the M87 black hole would be compared to Earth because of its gravity, i looked up the approximate mass of the black hole and some sourced say it is around 6.5x10^9 solar masses, so around 1.3x10^40 kilograms, then using the Schwarzschild radius equation i got a radius of 1,93x10^13 meters, i plugged in those numbers into the time dilation Schwarzschild formula and i got that for every hour close to the radius of the black hole about 24,9069 hours pass on Earth. Did i make a mistake in and of my assumptions? Should I consider the fact that the black hole is rotating? How do I include that in my calculations?