What is the escape velocity from the sun? And from the solar system?

The escape velocity depends on the distance (R) from Sun. For a circular orbit around Sun, the escape velocity is given by:

Here G is the gravitational constant, which is 6.674E-11 m3/kg/s2 and M is the mass of the Sun, which is 1.989E30 kg.

For instance Earth is at a distance of 149.6 million km. So escape velocity from solar system initiated from Earth orbit is 42.127 km/s. You can use the same formula to calculate the escape velocity from surface of individual planets by replacing mass of sun with mass of planet and R with radius of planet.