What is the value of Rydberg's constant?

What is the value of universal constant of gravitation G.

The value of Avogadro's constant

What is the value of root3(64)

What is the number of arbitrary constants in the particular solution of a differential equation of order 3?

What is the number of arbitrary constants in the general solution of a differential equation of order 2?

What is the value of charge on an electron?