20556390016800 has 1296 divisors, whose sum is σ = 83630159514720. Its totient is φ = 4922859110400.

The previous prime is 20556390016739. The next prime is 20556390016823. The reversal of 20556390016800 is 861009365502.

20556390016800 is a `hidden beast` number, since 2 + 0 + 5 + 5 + 639 + 0 + 0 + 1 + 6 + 8 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1296).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

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 215 ways as a sum of consecutive naturals, for example, 1952353936 + ... + 1952364464.

It is an arithmetic number, because the mean of its divisors is an integer number (64529444070).

Almost surely, 2^{20556390016800} is an apocalyptic number.

20556390016800 is a gapful number since it is divisible by the number (20) 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 20556390016800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41815079757360).

20556390016800 is an abundant number, since it is smaller than the sum of its proper divisors (63073769497920).

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

20556390016800 is a wasteful number, since it uses less digits than its factorization.

20556390016800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10669 (or 10633 counting only the distinct ones).

The product of its (nonzero) digits is 388800, while the sum is 45.

The spelling of 20556390016800 in words is "twenty trillion, five hundred fifty-six billion, three hundred ninety million, sixteen thousand, eight hundred".