The proton-to-electron mass ratio is a dimensionless quantity that expresses the mass of a proton in terms of the mass of an electron. Its value is approximately: \[ \frac{m_p}{m_e} \approx 1836.15267389 \] This means that a proton is about 1836 times more massive than an electron. This ratio is fundamental in physics, playing a crucial role in various areas, including atomic physics, particle physics, and cosmology.