128405556 has 36 divisors (see below), whose sum is σ = 343675332. Its totient is φ = 40283904.

The previous prime is 128405521. The next prime is 128405569. The reversal of 128405556 is 655504821.

It can be written as a sum of positive squares in 2 ways, for example, as 119902500 + 8503056 = 10950^2 + 2916^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 128405556.

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 104295 + ... + 105518.

It is an arithmetic number, because the mean of its divisors is an integer number (9546537).

Almost surely, 2^128405556 is an apocalyptic number.

It is an amenable number.

128405556 is an abundant number, since it is smaller than the sum of its proper divisors (215269776).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

128405556 is a wasteful number, since it uses less digits than its factorization.

128405556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 209840 (or 209835 counting only the distinct ones).

The product of its (nonzero) digits is 48000, while the sum is 36.

The square root of 128405556 is about 11331.6175367862. The cubic root of 128405556 is about 504.5001177051.

The spelling of 128405556 in words is "one hundred twenty-eight million, four hundred five thousand, five hundred fifty-six".