128997009 has 16 divisors (see below), whose sum is σ = 192330240. Its totient is φ = 85447440.

The previous prime is 128996981. The next prime is 128997073. The reversal of 128997009 is 900799821.

It is not a de Polignac number, because 128997009 - 2⁵ = 128996977 is a prime.

It is not an unprimeable number, because it can be changed into a prime (128997079) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10977 + ... + 19454.

It is an arithmetic number, because the mean of its divisors is an integer number (12020640).

Almost surely, 2^128997009 is an apocalyptic number.

It is an amenable number.

128997009 is a deficient number, since it is larger than the sum of its proper divisors (63333231).

128997009 is a wasteful number, since it uses less digits than its factorization.

128997009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30597 (or 30591 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 45.

The square root of 128997009 is about 11357.6850194043. The cubic root of 128997009 is about 505.2735295620.

The spelling of 128997009 in words is "one hundred twenty-eight million, nine hundred ninety-seven thousand, nine".