2021221728 has 96 divisors (see below), whose sum is σ = 5903100000. Its totient is φ = 672841728.

The previous prime is 2021221723. The next prime is 2021221733. The reversal of 2021221728 is 8271221202.

It is an interprime number because it is at equal distance from previous prime (2021221723) and next prime (2021221733).

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2021221723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1078200 + ... + 1080072.

It is an arithmetic number, because the mean of its divisors is an integer number (61490625).

Almost surely, 2^2021221728 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 2021221728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2951550000).

2021221728 is an abundant number, since it is smaller than the sum of its proper divisors (3881878272).

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

2021221728 is a wasteful number, since it uses less digits than its factorization.

2021221728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3141 (or 3127 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

The square root of 2021221728 is about 44957.9995996263. Note that the first 3 decimals coincide. The cubic root of 2021221728 is about 1264.3616641204.

The spelling of 2021221728 in words is "two billion, twenty-one million, two hundred twenty-one thousand, seven hundred twenty-eight".