One mole is equivalent to $6.02\times10^{23}$ particles. This value is known as the Avogadro constant ($N_{\text{A}}$). It was obtained by determining the number of atoms in $0.012\text{ kg}$ of carbon-12.
The number of particles $N$ is related to the number of moles $n$ by:$$N=nN_{\text{A}}$$
The molar gas constant $R$ is equivalent to $8.314\text{ m}^{2}\text{ kg}\text{ s}^{-2}\text{ K}^{-1}$. It is a commonly used universal constant in thermodynamic calculations.
The Boltzmann constant $k$ is equivalent to $1.38\times10^{-23}\text{m}^{2}\text{kgs}^{-2}K^{-1}$. It is related to the molar gas constant $R$ by:$$R=kN_{\text{A}}$$