21911814108 has 18 divisors (see below), whose sum is σ = 55388196864. Its totient is φ = 7303938024.

The previous prime is 21911814083. The next prime is 21911814121. The reversal of 21911814108 is 80141811912.

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 608661503 = 21911814108 / (2 + 1 + 9 + 1 + 1 + 8 + 1 + 4 + 1 + 0 + 8).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 304330716 + ... + 304330787.

It is an arithmetic number, because the mean of its divisors is an integer number (3077122048).

Almost surely, 2^21911814108 is an apocalyptic number.

It is an amenable number.

21911814108 is an abundant number, since it is smaller than the sum of its proper divisors (33476382756).

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

21911814108 is a wasteful number, since it uses less digits than its factorization.

21911814108 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 608661513 (or 608661508 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 36.

The spelling of 21911814108 in words is "twenty-one billion, nine hundred eleven million, eight hundred fourteen thousand, one hundred eight".