20993321664 has 336 divisors, whose sum is σ = 73743982560. Its totient is φ = 5835110400.

The previous prime is 20993321659. The next prime is 20993321683. The reversal of 20993321664 is 46612339902.

It is a tau number, because it is divible by the number of its divisors (336).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3129514 + ... + 3136214.

Almost surely, 2^20993321664 is an apocalyptic number.

20993321664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20993321664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36871991280).

20993321664 is an abundant number, since it is smaller than the sum of its proper divisors (52750660896).

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

20993321664 is a wasteful number, since it uses less digits than its factorization.

20993321664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6773 (or 6750 counting only the distinct ones).

The product of its (nonzero) digits is 419904, while the sum is 45.

The spelling of 20993321664 in words is "twenty billion, nine hundred ninety-three million, three hundred twenty-one thousand, six hundred sixty-four".