Function: ispowerful
Section: number_theoretical
C-Name: ispowerful
Prototype: lG
Help: ispowerful(x): true(1) if x is a powerful integer (valuation at all
 primes dividing x is greater than 1), false(0) if not.
Doc: true (1) if $x$ is a powerful integer, false (0) if not;
 an integer is powerful if and only if its valuation at all primes dividing
 $x$ is greater than 1.
 \bprog
 ? ispowerful(50)
 %1 = 0
 ? ispowerful(100)
 %2 = 1
 ? ispowerful(5^3*(10^1000+1)^2)
 %3 = 1
 @eprog
