21665995926 has 16 divisors (see below), whose sum is σ = 43420975104. Its totient is φ = 7207168104.

The previous prime is 21665995913. The next prime is 21665995979. The reversal of 21665995926 is 62959956612.

It is a self number, because there is not a number n which added to its sum of digits gives 21665995926.

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, 3704470 + ... + 3710313.

It is an arithmetic number, because the mean of its divisors is an integer number (2713810944).

Almost surely, 2^21665995926 is an apocalyptic number.

21665995926 is an abundant number, since it is smaller than the sum of its proper divisors (21754979178).

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

21665995926 is a wasteful number, since it uses less digits than its factorization.

21665995926 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7415275.

The product of its digits is 15746400, while the sum is 60.

The spelling of 21665995926 in words is "twenty-one billion, six hundred sixty-five million, nine hundred ninety-five thousand, nine hundred twenty-six".