The Compton Wavelength of a Proton is 1.32140985623E-15 m. The Compton wavelength is a quantum mechanical property of nuclear/atomic particles that is equivalent to the wavelength of a photon having the same wavelength as the rest mass of the particle. So, in this case, the Compton Wavelength of a proton represents the wavelength of a proton's rest mass.
This constant is specified with a standard uncertainty (standard deviation) of: 0.000 000 000 94 E-15 m