√2    1.41421                     Pythagoras' constant √2
NA    6.022e23 molecules/mole     Avogadro constant
c     299,792,458 or 2.998e8 m/s  Speed of light
C     6.241509e18 electrons       Coulomb
e     1.60217662e−19 C            electron charge
e     2.71828 1828                Euler's number
eV    1.6022e−19 J                electron volt
G     6.674e−11 m³/kg•s²          Gravitational constant
g     9.8 m/s²                    Earth, acceleration due to gravity
h     6.62607e−34 Js              Planck constant
H₀    70 (km/s)/Mpc (mega parsec) Hubble's Constant
i     √(–1)                       Imaginary unit i
Patm  1.01e5 N/m² or 101 kPa      Earth atmosphere pressure
R     0.08206 (atm•L)/(mol•K)     gas constant
         or 8.314 J/K•mol
H₂O   2.06 kJ/kgC                 specific heat of ice
      2.1 kJ/kgC                  specific heat of steam
      2256 kJ/kg                  heat of vaporization of water
      273.16K (0.01°C)            triple point of water
      334 kJ/kg                   heat of fusion of ice
      4.186 kJ/kg•C               specific heat of water
ε₀    8.854e−12 F/m               electric constant (vacuum permittivity)
μ₀    4π×10^−7 H/m                magnetic constant (vacuum permeability)
π     3.14159 26536               pi, Archimedes' constant
σ     5.670367e−8 W/m²•K⁴         Stefan–Boltzmann constant
kʙ    1.3806×10^−23 J/K           Boltzmann constant (energy in a gas molecule)
φ     1.61803                     Golden ratio

e =
2.71828 18284 59045 23536 02874 71352 66249 77572 47093 69995 95749
  66967 62772 40766 30353 54759 45713 82178 52516 64274
π =
3.14159 26535 89793 23846 26433 83279 50288 41971 69399 37510 58209
  74944 59230 78164 06286 20899 86280 34825 34211 70679 82148 08651
  32823 06647 09384 46095 50582 23172 53594 08128 48111 74502 84102