2121728 has 56 divisors (see below), whose sum is σ = 4980432. Its totient is φ = 884736.

The previous prime is 2121683. The next prime is 2121737. The reversal of 2121728 is 8271212.

It is a tau number, because it is divible by the number of its divisors (56).

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (3) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57326 + ... + 57362.

2^2121728 is an apocalyptic number.

2121728 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 2121728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2490216).

2121728 is an abundant number, since it is smaller than the sum of its proper divisors (2858704).

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

2121728 is an frugal number, since it uses more digits than its factorization.

2121728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70 (or 46 counting only the distinct ones).

The product of its digits is 448, while the sum is 23.

The square root of 2121728 is about 1456.6152546229. The cubic root of 2121728 is about 128.4980594922.

The spelling of 2121728 in words is "two million, one hundred twenty-one thousand, seven hundred twenty-eight".