21878892 has 108 divisors (see below), whose sum is σ = 65563680. Its totient is φ = 6132672.

The previous prime is 21878887. The next prime is 21878893. The reversal of 21878892 is 29887812.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21878893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 139278 + ... + 139434.

Almost surely, 2^21878892 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 21878892, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32781840).

21878892 is an abundant number, since it is smaller than the sum of its proper divisors (43684788).

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

21878892 is a wasteful number, since it uses less digits than its factorization.

21878892 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 260 (or 248 counting only the distinct ones).

The product of its digits is 129024, while the sum is 45.

The square root of 21878892 is about 4677.4877872636. The cubic root of 21878892 is about 279.6888209648.

The spelling of 21878892 in words is "twenty-one million, eight hundred seventy-eight thousand, eight hundred ninety-two".