128998905 has 32 divisors (see below), whose sum is σ = 243499008. Its totient is φ = 57067200.

The previous prime is 128998901. The next prime is 128998913. The reversal of 128998905 is 509899821.

It is not a de Polignac number, because 128998905 - 2² = 128998901 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (128998901) 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 31 ways as a sum of consecutive naturals, for example, 16561 + ... + 23070.

It is an arithmetic number, because the mean of its divisors is an integer number (7609344).

Almost surely, 2^128998905 is an apocalyptic number.

128998905 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

128998905 is a deficient number, since it is larger than the sum of its proper divisors (114500103).

128998905 is a wasteful number, since it uses less digits than its factorization.

128998905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39677.

The product of its (nonzero) digits is 466560, while the sum is 51.

The square root of 128998905 is about 11357.7684868111. The cubic root of 128998905 is about 505.2760050559.

The spelling of 128998905 in words is "one hundred twenty-eight million, nine hundred ninety-eight thousand, nine hundred five".