判斷到根號n就好了

from sys import stdin
for s in stdin:
 n=int(s)
 if not n:
  break
 print(f'{n} : ',end='')
 ans=0
 for i in range(2,int(n**0.5)+1):
  if not n%i:
   ans+=1
  while not n%i:
   n//=i
  if n==1:
   break
 if n!=1:
  ans+=1
 print(ans)