921665718912 has 128 divisors (see below), whose sum is σ = 2578019400000. Its totient is φ = 290940125184.

The previous prime is 921665718907. The next prime is 921665718937. The reversal of 921665718912 is 219817566129.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (57).

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 15 ways as a sum of consecutive naturals, for example, 20033728 + ... + 20079680.

Almost surely, 2^921665718912 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 921665718912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1289009700000).

921665718912 is an abundant number, since it is smaller than the sum of its proper divisors (1656353681088).

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

921665718912 is a wasteful number, since it uses less digits than its factorization.

921665718912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48738 (or 48726 counting only the distinct ones).

The product of its digits is 3265920, while the sum is 57.

The spelling of 921665718912 in words is "nine hundred twenty-one billion, six hundred sixty-five million, seven hundred eighteen thousand, nine hundred twelve".