20556863964 has 768 divisors, whose sum is σ = 74059776000. Its totient is φ = 4938071040.

The previous prime is 20556863963. The next prime is 20556863969. The reversal of 20556863964 is 46936865502.

20556863964 is a `hidden beast` number, since 2 + 0 + 556 + 86 + 3 + 9 + 6 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 20556863964.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20556863963) 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 255 ways as a sum of consecutive naturals, for example, 663124629 + ... + 663124659.

It is an arithmetic number, because the mean of its divisors is an integer number (96432000).

Almost surely, 2^20556863964 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 20556863964, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37029888000).

20556863964 is an abundant number, since it is smaller than the sum of its proper divisors (53502912036).

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

20556863964 is a wasteful number, since it uses less digits than its factorization.

20556863964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107 (or 73 counting only the distinct ones).

The product of its (nonzero) digits is 9331200, while the sum is 54.

The spelling of 20556863964 in words is "twenty billion, five hundred fifty-six million, eight hundred sixty-three thousand, nine hundred sixty-four".