128266189 has 4 divisors (see below), whose sum is σ = 132403840. Its totient is φ = 124128540.

The previous prime is 128266157. The next prime is 128266199. The reversal of 128266189 is 981662821.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 128266189 - 2⁵ = 128266157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128266129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2068779 + ... + 2068840.

It is an arithmetic number, because the mean of its divisors is an integer number (33100960).

Almost surely, 2^128266189 is an apocalyptic number.

It is an amenable number.

128266189 is a deficient number, since it is larger than the sum of its proper divisors (4137651).

128266189 is an equidigital number, since it uses as much as digits as its factorization.

128266189 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4137650.

The product of its digits is 82944, while the sum is 43.

The square root of 128266189 is about 11325.4663921624. The cubic root of 128266189 is about 504.3175292381.

The spelling of 128266189 in words is "one hundred twenty-eight million, two hundred sixty-six thousand, one hundred eighty-nine".