2128809728 has 72 divisors (see below), whose sum is σ = 4490095680. Its totient is φ = 1005670400.

The previous prime is 2128809707. The next prime is 2128809733. The reversal of 2128809728 is 8279088212.

It is a Harshad number since it is a multiple of its sum of digits (47).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 345878 + ... + 351978.

It is an arithmetic number, because the mean of its divisors is an integer number (62362440).

Almost surely, 2^2128809728 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 2128809728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2245047840).

2128809728 is an abundant number, since it is smaller than the sum of its proper divisors (2361285952).

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

2128809728 is an equidigital number, since it uses as much as digits as its factorization.

2128809728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6193 (or 6179 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 47.

The square root of 2128809728 is about 46139.0260842164. The cubic root of 2128809728 is about 1286.4086412297.

The spelling of 2128809728 in words is "two billion, one hundred twenty-eight million, eight hundred nine thousand, seven hundred twenty-eight".