128508905 has 16 divisors (see below), whose sum is σ = 178475520. Its totient is φ = 87003072.

The previous prime is 128508893. The next prime is 128508907. The reversal of 128508905 is 509805821.

It is a cyclic number.

It is not a de Polignac number, because 128508905 - 2²⁰ = 127460329 is a prime.

It is not an unprimeable number, because it can be changed into a prime (128508907) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20474 + ... + 26003.

It is an arithmetic number, because the mean of its divisors is an integer number (11154720).

Almost surely, 2^128508905 is an apocalyptic number.

It is an amenable number.

128508905 is a deficient number, since it is larger than the sum of its proper divisors (49966615).

128508905 is an equidigital number, since it uses as much as digits as its factorization.

128508905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46568.

The product of its (nonzero) digits is 28800, while the sum is 38.

The square root of 128508905 is about 11336.1768246618. The cubic root of 128508905 is about 504.6354327234.

The spelling of 128508905 in words is "one hundred twenty-eight million, five hundred eight thousand, nine hundred five".