20993634816 has 320 divisors, whose sum is σ = 70285501440. Its totient is φ = 5409423360.

The previous prime is 20993634757. The next prime is 20993634817. The reversal of 20993634816 is 61843639902.

It is not an unprimeable number, because it can be changed into a prime (20993634817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16439170 + ... + 16440446.

It is an arithmetic number, because the mean of its divisors is an integer number (219642192).

Almost surely, 2^20993634816 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 20993634816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35142750720).

20993634816 is an abundant number, since it is smaller than the sum of its proper divisors (49291866624).

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

20993634816 is a wasteful number, since it uses less digits than its factorization.

20993634816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1455 (or 1439 counting only the distinct ones).

The product of its (nonzero) digits is 1679616, while the sum is 51.

The spelling of 20993634816 in words is "twenty billion, nine hundred ninety-three million, six hundred thirty-four thousand, eight hundred sixteen".