128188905 has 64 divisors (see below), whose sum is σ = 230334720. Its totient is φ = 60466176.

The previous prime is 128188901. The next prime is 128188939. The reversal of 128188905 is 509881821.

It is not a de Polignac number, because 128188905 - 2² = 128188901 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (128188901) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 786354 + ... + 786516.

It is an arithmetic number, because the mean of its divisors is an integer number (3598980).

Almost surely, 2^128188905 is an apocalyptic number.

128188905 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

128188905 is a deficient number, since it is larger than the sum of its proper divisors (102145815).

128188905 is a wasteful number, since it uses less digits than its factorization.

128188905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330.

The product of its (nonzero) digits is 46080, while the sum is 42.

The square root of 128188905 is about 11322.0539214402. The cubic root of 128188905 is about 504.2162203719.

The spelling of 128188905 in words is "one hundred twenty-eight million, one hundred eighty-eight thousand, nine hundred five".