A complex number is said to be hypertranscendental if it is not the value at an of a function which is the solution of an algebraic differential equation with coefficients in Z[r] and with algebraic initial conditions. The term was introduced by D. D. Morduhai-Boltovskoi in "Hypertranscendental numbers and hypertranscendental functions" (1949). Any hypertranscendental number is also a transcendental number.