128865009 has 64 divisors (see below), whose sum is σ = 224663040. Its totient is φ = 63866880.

The previous prime is 128865007. The next prime is 128865017. The reversal of 128865009 is 900568821.

It is not a de Polignac number, because 128865009 - 2¹ = 128865007 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (128865007) 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, 324399 + ... + 324795.

It is an arithmetic number, because the mean of its divisors is an integer number (3510360).

Almost surely, 2^128865009 is an apocalyptic number.

It is an amenable number.

128865009 is a deficient number, since it is larger than the sum of its proper divisors (95798031).

128865009 is a wasteful number, since it uses less digits than its factorization.

128865009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 490.

The product of its (nonzero) digits is 34560, while the sum is 39.

The square root of 128865009 is about 11351.8724887130. The cubic root of 128865009 is about 505.1011253878.

The spelling of 128865009 in words is "one hundred twenty-eight million, eight hundred sixty-five thousand, nine".