128555856 has 160 divisors (see below), whose sum is σ = 433722240. Its totient is φ = 35942400.

The previous prime is 128555851. The next prime is 128555897. The reversal of 128555856 is 658555821.

128555856 is a `hidden beast` number, since 12 + 8 + 55 + 585 + 6 = 666.

It is a super-2 number, since 2×128555856² = 33053216223785472, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128555851) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 60736 + ... + 62816.

It is an arithmetic number, because the mean of its divisors is an integer number (2710764).

Almost surely, 2^128555856 is an apocalyptic number.

128555856 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 128555856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (216861120).

128555856 is an abundant number, since it is smaller than the sum of its proper divisors (305166384).

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

128555856 is a wasteful number, since it uses less digits than its factorization.

128555856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2122 (or 2110 counting only the distinct ones).

The product of its digits is 480000, while the sum is 45.

The square root of 128555856 is about 11338.2474836281. The cubic root of 128555856 is about 504.6968817811.

The spelling of 128555856 in words is "one hundred twenty-eight million, five hundred fifty-five thousand, eight hundred fifty-six".