21855896188 has 24 divisors (see below), whose sum is σ = 45612306432. Its totient is φ = 8959559664.

The previous prime is 21855896177. The next prime is 21855896207. The reversal of 21855896188 is 88169855812.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16968220 + ... + 16969507.

It is an arithmetic number, because the mean of its divisors is an integer number (1900512768).

Almost surely, 2^21855896188 is an apocalyptic number.

21855896188 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21855896188 is an abundant number, since it is smaller than the sum of its proper divisors (23756410244).

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

21855896188 is a wasteful number, since it uses less digits than its factorization.

21855896188 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33937761 (or 33937759 counting only the distinct ones).

The product of its digits is 11059200, while the sum is 61.

The spelling of 21855896188 in words is "twenty-one billion, eight hundred fifty-five million, eight hundred ninety-six thousand, one hundred eighty-eight".