20646555552 has 144 divisors (see below), whose sum is σ = 68529307392. Its totient is φ = 5773478400.

The previous prime is 20646555533. The next prime is 20646555557. The reversal of 20646555552 is 25555564602.

20646555552 is a `hidden beast` number, since 2 + 0 + 6 + 46 + 5 + 55 + 552 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a junction number, because it is equal to n+sod(n) for n = 20646555498 and 20646555507.

It is not an unprimeable number, because it can be changed into a prime (20646555557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14199 + ... + 203702.

It is an arithmetic number, because the mean of its divisors is an integer number (475897968).

Almost surely, 2^20646555552 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 20646555552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34264653696).

20646555552 is an abundant number, since it is smaller than the sum of its proper divisors (47882751840).

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

20646555552 is a wasteful number, since it uses less digits than its factorization.

20646555552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 217971 (or 217960 counting only the distinct ones).

The product of its (nonzero) digits is 1800000, while the sum is 45.

The spelling of 20646555552 in words is "twenty billion, six hundred forty-six million, five hundred fifty-five thousand, five hundred fifty-two".