21990118812 has 12 divisors (see below), whose sum is σ = 51310277256. Its totient is φ = 7330039600.

The previous prime is 21990118763. The next prime is 21990118823. The reversal of 21990118812 is 21881109912.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 916254939 + ... + 916254962.

It is an arithmetic number, because the mean of its divisors is an integer number (4275856438).

Almost surely, 2^21990118812 is an apocalyptic number.

It is an amenable number.

21990118812 is an abundant number, since it is smaller than the sum of its proper divisors (29320158444).

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

21990118812 is a wasteful number, since it uses less digits than its factorization.

21990118812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1832509908 (or 1832509906 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 42.

The spelling of 21990118812 in words is "twenty-one billion, nine hundred ninety million, one hundred eighteen thousand, eight hundred twelve".