21105792 has 128 divisors (see below), whose sum is σ = 64627200. Its totient is φ = 6773760.

The previous prime is 21105781. The next prime is 21105811. The reversal of 21105792 is 29750112.

It is a tau number, because it is divible by the number of its divisors (128).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 107038 + ... + 107234.

It is an arithmetic number, because the mean of its divisors is an integer number (504900).

Almost surely, 2^21105792 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 21105792, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32313600).

21105792 is an abundant number, since it is smaller than the sum of its proper divisors (43521408).

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

21105792 is a wasteful number, since it uses less digits than its factorization.

21105792 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 251 (or 233 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 27.

The square root of 21105792 is about 4594.1040475810. The cubic root of 21105792 is about 276.3549308934.

The spelling of 21105792 in words is "twenty-one million, one hundred five thousand, seven hundred ninety-two".