128556720 has 240 divisors, whose sum is σ = 475282080. Its totient is φ = 32182272.

The previous prime is 128556697. The next prime is 128556733. The reversal of 128556720 is 27655821.

It is a happy number.

128556720 is a `hidden beast` number, since 12 + 85 + 567 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

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

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 330286 + ... + 330674.

It is an arithmetic number, because the mean of its divisors is an integer number (1980342).

Almost surely, 2^128556720 is an apocalyptic number.

128556720 is a gapful number since it is divisible by the number (10) 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 128556720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (237641040).

128556720 is an abundant number, since it is smaller than the sum of its proper divisors (346725360).

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

128556720 is a wasteful number, since it uses less digits than its factorization.

128556720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 434 (or 416 counting only the distinct ones).

The product of its (nonzero) digits is 33600, while the sum is 36.

The square root of 128556720 is about 11338.2855846905. The cubic root of 128556720 is about 504.6980124365.

The spelling of 128556720 in words is "one hundred twenty-eight million, five hundred fifty-six thousand, seven hundred twenty".