#!python3
import sys, math
x = int(input())
if x == 1:
   print(1)
   exit(0)
def cf(x):
   r = 1
   for f in range(2, 32000):
      if x % f == 0:
         e = 0
         while x % f == 0:
            e += 1
            x //= f
         r *= e+1
   if x > 1:
      r *= 2
   return r
for e in range(2, 64):
   if e == 2:
      z = math.isqrt(x)
   else:
      z = 1
      while (z+1)**e <= x:
         z += 1
   if z**e == x and cf(z) == e:
      print(z)
      sys.exit(0)
print(-1)