What is the wavelength of a photon that has 1000 times as much energy as a photon a wavelength of 511 nm?

Would it be more dangerous to be exposed to 1 million photons with a wavelength of 511 nm or 1000 photons each with 1000 times the energy of a 511-nm photon? Why?

It would be more dangerous to be exposed to 1000 photons with 1000 times the energy of a 511-nm photon than to 1 million photons with a wavelength of 511-nm. This is because the photons are in the X-ray spectrum, and therefore they are more dangerous.

The wavelength of a photon that has 1000 times as much energy as a photon a wavelength of 511 nm is λ =  __nm.