assuming an ellipsoid, the volume is about 230,000 m^3
(4*610^2 * 150 * 3.1415/3)

Mean density of asteroids = 2,650 Kg/m^3

Mass of asteroid is about
609,500,000 Kg

velocity = 3,500 m/sec

Kinetic energy
E = mv^2/2

E = (609,500,000 X 3,500^2)/2

E = 3.7 X 10^15 joules

The Hiroshima bomb was a 20kT explosion releasing 8X10^13 joules

So the asteroid would be like 100 Hiroshima blasts or a 2 megaton bomb. The USSR busted one that was 50mT which would be considerably larger than the asteroid and we did okay after that.

I think the planet killer is supposedly several cubic kilometers in volume which is at least 10 times the size of this asteroid.