21088392 has 64 divisors (see below), whose sum is σ = 57214080. Its totient is φ = 6438912.

The previous prime is 21088373. The next prime is 21088393. The reversal of 21088392 is 29388012.

It is not an unprimeable number, because it can be changed into a prime (21088393) 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, 80053 + ... + 80315.

It is an arithmetic number, because the mean of its divisors is an integer number (893970).

Almost surely, 2^21088392 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 21088392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28607040).

21088392 is an abundant number, since it is smaller than the sum of its proper divisors (36125688).

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

21088392 is a wasteful number, since it uses less digits than its factorization.

21088392 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 542 (or 538 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 33.

The square root of 21088392 is about 4592.2099255152. The cubic root of 21088392 is about 276.2789659983.

The spelling of 21088392 in words is "twenty-one million, eighty-eight thousand, three hundred ninety-two".