128765664 has 72 divisors (see below), whose sum is σ = 369080712. Its totient is φ = 42581760.

The previous prime is 128765653. The next prime is 128765683. The reversal of 128765664 is 466567821.

128765664 is a `hidden beast` number, since 1 + 2 + 87 + 6 + 566 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 36022 + ... + 39434.

It is an arithmetic number, because the mean of its divisors is an integer number (5126121).

Almost surely, 2^128765664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 128765664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (184540356).

128765664 is an abundant number, since it is smaller than the sum of its proper divisors (240315048).

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

128765664 is a wasteful number, since it uses less digits than its factorization.

128765664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3560 (or 3549 counting only the distinct ones).

The product of its digits is 483840, while the sum is 45.

The square root of 128765664 is about 11347.4959352273. The cubic root of 128765664 is about 504.9712939929.

The spelling of 128765664 in words is "one hundred twenty-eight million, seven hundred sixty-five thousand, six hundred sixty-four".