I highly recommend Dragon's Egg, a hard sci fi novel by Robert L. Forward, as well as its sequel, Starquake, for anyone wanting to expand their mind with a fascinating portrayal of neutron star physics, dealing with the hypothetical possibility of life on their surfaces. The relative physical scales of time, space, velocities and forces are mind-boggling compared to our normal intuition.
The radius of neutron stars is measured in small multiples of the Swarzschild radius for the mass of the star. That is, the radius at which the star would become a black hole.