128856591 has 6 divisors (see below), whose sum is σ = 186126200. Its totient is φ = 85904388.

The previous prime is 128856577. The next prime is 128856593. The reversal of 128856591 is 195658821.

It is a happy number.

128856591 is a `hidden beast` number, since 1 + 2 + 8 + 8 + 56 + 591 = 666.

It is not a de Polignac number, because 128856591 - 2¹⁰ = 128855567 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128856593) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7158691 + ... + 7158708.

Almost surely, 2^128856591 is an apocalyptic number.

128856591 is a deficient number, since it is larger than the sum of its proper divisors (57269609).

128856591 is a wasteful number, since it uses less digits than its factorization.

128856591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14317405 (or 14317402 counting only the distinct ones).

The product of its digits is 172800, while the sum is 45.

The square root of 128856591 is about 11351.5017068228. The cubic root of 128856591 is about 505.0901267107.

The spelling of 128856591 in words is "one hundred twenty-eight million, eight hundred fifty-six thousand, five hundred ninety-one".