A neutron has a mass of $1.675 \times 10^{-27} \text{ kg}$. Calculate its De Broglie wavelength if it is traveling at $2000 \text{ m/s}$ ($h = 6.626 \times 10^{-34} \text{ J}\cdot\text{s}$, $\lambda = \frac{h}{mv}$).