How many photons are in a laser pulse of 0.363J at 657 nm?

We know that the energy of a wave is given by:

E = nhc/λ; where n is the number of photons, h is the Planck's constant, c is the speed of light and λ is the wavelength. Substituting values:

0.363 = (n x 6.63 x 10⁻³⁴ x 3 x 10⁸) / (657 x 10⁻⁹)

n = 1.2 x 10¹⁸ photons