21868392 has 256 divisors, whose sum is σ = 77414400. Its totient is φ = 4976640.

The previous prime is 21868367. The next prime is 21868393. The reversal of 21868392 is 29386812.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (39).

Its product of digits (41472) is a multiple of the sum of its prime factors (96).

It is a self number, because there is not a number n which added to its sum of digits gives 21868392.

It is not an unprimeable number, because it can be changed into a prime (21868393) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 705417 + ... + 705447.

It is an arithmetic number, because the mean of its divisors is an integer number (302400).

Almost surely, 2^21868392 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 21868392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38707200).

21868392 is an abundant number, since it is smaller than the sum of its proper divisors (55546008).

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

21868392 is a wasteful number, since it uses less digits than its factorization.

21868392 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96 (or 92 counting only the distinct ones).

The product of its digits is 41472, while the sum is 39.

The square root of 21868392 is about 4676.3652551955. The cubic root of 21868392 is about 279.6440715546.

The spelling of 21868392 in words is "twenty-one million, eight hundred sixty-eight thousand, three hundred ninety-two".