21022188 has 48 divisors (see below), whose sum is σ = 54332544. Its totient is φ = 6272640.

The previous prime is 21022171. The next prime is 21022193. The reversal of 21022188 is 88122012.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7656 + ... + 10032.

It is an arithmetic number, because the mean of its divisors is an integer number (1131928).

Almost surely, 2^21022188 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 21022188, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27166272).

21022188 is an abundant number, since it is smaller than the sum of its proper divisors (33310356).

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

21022188 is a wasteful number, since it uses less digits than its factorization.

21022188 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2462 (or 2460 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 24.

The square root of 21022188 is about 4584.9959651018. The cubic root of 21022188 is about 275.9895501190.

The spelling of 21022188 in words is "twenty-one million, twenty-two thousand, one hundred eighty-eight".