20912845664 has 96 divisors (see below), whose sum is σ = 44704620576. Its totient is φ = 9591644160.

The previous prime is 20912845663. The next prime is 20912845693. The reversal of 20912845664 is 46654821902.

It is a super-2 number, since 2×20912845664² (a number of 21 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (47) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20912845663) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17707154 + ... + 17708334.

It is an arithmetic number, because the mean of its divisors is an integer number (465673131).

Almost surely, 2^20912845664 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 20912845664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22352310288).

20912845664 is an abundant number, since it is smaller than the sum of its proper divisors (23791774912).

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

20912845664 is a wasteful number, since it uses less digits than its factorization.

20912845664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2008 (or 2000 counting only the distinct ones).

The product of its (nonzero) digits is 829440, while the sum is 47.

The spelling of 20912845664 in words is "twenty billion, nine hundred twelve million, eight hundred forty-five thousand, six hundred sixty-four".