21866112 has 192 divisors, whose sum is σ = 70543200. Its totient is φ = 6718464.

The previous prime is 21866111. The next prime is 21866113. The reversal of 21866112 is 21166812.

It is an interprime number because it is at equal distance from previous prime (21866111) and next prime (21866113).

It is a tau number, because it is divible by the number of its divisors (192).

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

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21866111) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 590958 + ... + 590994.

Almost surely, 2^21866112 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 21866112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35271600).

21866112 is an abundant number, since it is smaller than the sum of its proper divisors (48677088).

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

21866112 is an equidigital number, since it uses as much as digits as its factorization.

21866112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85 (or 61 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 21866112 is about 4676.1214697653. The cubic root of 21866112 is about 279.6343526470.

21866112 divided by its product of digits (1152) gives a palindrome (18981).

The spelling of 21866112 in words is "twenty-one million, eight hundred sixty-six thousand, one hundred twelve".