20947816512 has 224 divisors, whose sum is σ = 70756515840. Its totient is φ = 5953098240.

The previous prime is 20947816441. The next prime is 20947816523. The reversal of 20947816512 is 21561874902.

20947816512 is a `hidden beast` number, since 2 + 0 + 9 + 478 + 165 + 12 = 666.

It is a tau number, because it is divible by the number of its divisors (224).

It is a super-2 number, since 2×20947816512² (a number of 21 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2305803 + ... + 2314869.

Almost surely, 2^20947816512 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 20947816512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35378257920).

20947816512 is an abundant number, since it is smaller than the sum of its proper divisors (49808699328).

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

20947816512 is a wasteful number, since it uses less digits than its factorization.

20947816512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9286 (or 9270 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 45.

The spelling of 20947816512 in words is "twenty billion, nine hundred forty-seven million, eight hundred sixteen thousand, five hundred twelve".