128555409 has 16 divisors (see below), whose sum is σ = 175120704. Its totient is φ = 83865600.

The previous prime is 128555389. The next prime is 128555417. The reversal of 128555409 is 904555821.

It is not a de Polignac number, because 128555409 - 2⁷ = 128555281 is a prime.

It is not an unprimeable number, because it can be changed into a prime (128555489) 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, 26449 + ... + 30929.

It is an arithmetic number, because the mean of its divisors is an integer number (10945044).

Almost surely, 2^128555409 is an apocalyptic number.

It is an amenable number.

128555409 is a deficient number, since it is larger than the sum of its proper divisors (46565295).

128555409 is a wasteful number, since it uses less digits than its factorization.

128555409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4688.

The product of its (nonzero) digits is 72000, while the sum is 39.

The square root of 128555409 is about 11338.2277715699. The cubic root of 128555409 is about 504.6962968219.

The spelling of 128555409 in words is "one hundred twenty-eight million, five hundred fifty-five thousand, four hundred nine".