2121889728 has 168 divisors, whose sum is σ = 6691268304. Its totient is φ = 591360000.

The previous prime is 2121889723. The next prime is 2121889753. The reversal of 2121889728 is 8279881212.

It is a tau number, because it is divible by the number of its divisors (168).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121889723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 382978 + ... + 388478.

It is an arithmetic number, because the mean of its divisors is an integer number (39828978).

Almost surely, 2^2121889728 is an apocalyptic number.

2121889728 is a gapful number since it is divisible by the number (28) 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 2121889728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3345634152).

2121889728 is an abundant number, since it is smaller than the sum of its proper divisors (4569378576).

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

2121889728 is a wasteful number, since it uses less digits than its factorization.

2121889728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5571 (or 5554 counting only the distinct ones).

The product of its digits is 258048, while the sum is 48.

The square root of 2121889728 is about 46063.9742966236. The cubic root of 2121889728 is about 1285.0132431627.

The spelling of 2121889728 in words is "two billion, one hundred twenty-one million, eight hundred eighty-nine thousand, seven hundred twenty-eight".