21909809668 has 12 divisors (see below), whose sum is σ = 38348613072. Its totient is φ = 10953063080.

The previous prime is 21909809659. The next prime is 21909809681. The reversal of 21909809668 is 86690890912.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 433498 + ... + 481393.

It is an arithmetic number, because the mean of its divisors is an integer number (3195717756).

Almost surely, 2^21909809668 is an apocalyptic number.

It is an amenable number.

21909809668 is a deficient number, since it is larger than the sum of its proper divisors (16438803404).

21909809668 is a wasteful number, since it uses less digits than its factorization.

21909809668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 920882 (or 920880 counting only the distinct ones).

The product of its (nonzero) digits is 3359232, while the sum is 58.

The spelling of 21909809668 in words is "twenty-one billion, nine hundred nine million, eight hundred nine thousand, six hundred sixty-eight".