128556405 has 12 divisors (see below), whose sum is σ = 222831180. Its totient is φ = 68563392.

The previous prime is 128556403. The next prime is 128556419. The reversal of 128556405 is 504655821.

128556405 is a `hidden beast` number, since 1 + 2 + 8 + 5 + 5 + 640 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 30902481 + 97653924 = 5559^2 + 9882^2 .

It is not a de Polignac number, because 128556405 - 2¹ = 128556403 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 128556405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128556403) 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 11 ways as a sum of consecutive naturals, for example, 1428360 + ... + 1428449.

It is an arithmetic number, because the mean of its divisors is an integer number (18569265).

Almost surely, 2^128556405 is an apocalyptic number.

128556405 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

128556405 is a deficient number, since it is larger than the sum of its proper divisors (94274775).

128556405 is a wasteful number, since it uses less digits than its factorization.

128556405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2856820 (or 2856817 counting only the distinct ones).

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

The square root of 128556405 is about 11338.2716936930. The cubic root of 128556405 is about 504.6976002190.

The spelling of 128556405 in words is "one hundred twenty-eight million, five hundred fifty-six thousand, four hundred five".