128251728 has 160 divisors (see below), whose sum is σ = 406581120. Its totient is φ = 38384640.

The previous prime is 128251709. The next prime is 128251769. The reversal of 128251728 is 827152821.

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

It is a junction number, because it is equal to n+sod(n) for n = 128251692 and 128251701.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 650926 + ... + 651122.

It is an arithmetic number, because the mean of its divisors is an integer number (2541132).

Almost surely, 2^128251728 is an apocalyptic number.

128251728 is a gapful number since it is divisible by the number (18) 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 128251728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (203290560).

128251728 is an abundant number, since it is smaller than the sum of its proper divisors (278329392).

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

128251728 is a wasteful number, since it uses less digits than its factorization.

128251728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 362 (or 350 counting only the distinct ones).

The product of its digits is 17920, while the sum is 36.

The square root of 128251728 is about 11324.8279457129. The cubic root of 128251728 is about 504.2985759194.

The spelling of 128251728 in words is "one hundred twenty-eight million, two hundred fifty-one thousand, seven hundred twenty-eight".