21081792 has 56 divisors (see below), whose sum is σ = 58724800. Its totient is φ = 6656256.

The previous prime is 21081791. The next prime is 21081793. The reversal of 21081792 is 29718012.

It is an interprime number because it is at equal distance from previous prime (21081791) and next prime (21081793).

It is not an unprimeable number, because it can be changed into a prime (21081791) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 759 + ... + 6537.

Almost surely, 2^21081792 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 21081792, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29362400).

21081792 is an abundant number, since it is smaller than the sum of its proper divisors (37643008).

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

21081792 is a wasteful number, since it uses less digits than its factorization.

21081792 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5813 (or 5803 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 30.

The square root of 21081792 is about 4591.4912610175. The cubic root of 21081792 is about 276.2501407969.

The spelling of 21081792 in words is "twenty-one million, eighty-one thousand, seven hundred ninety-two".