128644938720 has 240 divisors, whose sum is σ = 455888941200. Its totient is φ = 34304477184.

The previous prime is 128644938683. The next prime is 128644938727. The reversal of 128644938720 is 27839446821.

128644938720 is a `hidden beast` number, since 1 + 2 + 86 + 4 + 493 + 8 + 72 + 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 (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128644938727) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 3128856 + ... + 3169704.

It is an arithmetic number, because the mean of its divisors is an integer number (1899537255).

Almost surely, 2^128644938720 is an apocalyptic number.

128644938720 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 128644938720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (227944470600).

128644938720 is an abundant number, since it is smaller than the sum of its proper divisors (327244002480).

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

128644938720 is an frugal number, since it uses more digits than its factorization.

128644938720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40891 (or 40859 counting only the distinct ones).

The product of its (nonzero) digits is 4644864, while the sum is 54.

The spelling of 128644938720 in words is "one hundred twenty-eight billion, six hundred forty-four million, nine hundred thirty-eight thousand, seven hundred twenty".