What is the least number that has 4 odd factors that are all the same

Factors can't be one the factors have to be Odd and the same I would say 3*3*3*3 would be equal to 9*9 = 81 the number 81 has four of factors that are all the same can't be one because one does not count as a factor a prime number has two factors one and itself every number has a factor of one and itself.