21792 has 24 divisors (see below), whose sum is σ = 57456. Its totient is φ = 7232.

The previous prime is 21787. The next prime is 21799. The reversal of 21792 is 29712.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (24).

It is a plaindrome in base 15.

It is a nialpdrome in base 16.

It is a zygodrome in base 15.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 21792.

It is not an unprimeable number, because it can be changed into a prime (21799) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18 + ... + 209.

It is an arithmetic number, because the mean of its divisors is an integer number (2394).

2²¹⁷⁹² 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 21792, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28728).

21792 is an abundant number, since it is smaller than the sum of its proper divisors (35664).

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

21792 is a wasteful number, since it uses less digits than its factorization.

21792 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240 (or 232 counting only the distinct ones).

The product of its digits is 252, while the sum is 21.

The square root of 21792 is about 147.6211366980. The cubic root of 21792 is about 27.9318068416.

The spelling of 21792 in words is "twenty-one thousand, seven hundred ninety-two".