128657520 has 60 divisors (see below), whose sum is σ = 432077256. Its totient is φ = 34308480.

The previous prime is 128657509. The next prime is 128657527. The reversal of 128657520 is 25756821.

It is a happy number.

128657520 is a `hidden beast` number, since 1 + 2 + 86 + 57 + 520 = 666.

It is a tau number, because it is divible by the number of its divisors (60).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128657527) by changing a digit.

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, 88626 + ... + 90065.

Almost surely, 2^128657520 is an apocalyptic number.

128657520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

128657520 is an abundant number, since it is smaller than the sum of its proper divisors (303419736).

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

128657520 is a wasteful number, since it uses less digits than its factorization.

128657520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178710 (or 178701 counting only the distinct ones).

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

The square root of 128657520 is about 11342.7298301599. The cubic root of 128657520 is about 504.8298874796.

The spelling of 128657520 in words is "one hundred twenty-eight million, six hundred fifty-seven thousand, five hundred twenty".