18561916800 has 768 divisors, whose sum is σ = 79409203200. Its totient is φ = 4146094080.

The previous prime is 18561916787. The next prime is 18561916811. The reversal of 18561916800 is 861916581.

18561916800 is a `hidden beast` number, since 1 + 8 + 561 + 9 + 1 + 6 + 80 + 0 = 666.

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

It is a congruent number.

It is an unprimeable number.

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 95 ways as a sum of consecutive naturals, for example, 28425274 + ... + 28425926.

It is an arithmetic number, because the mean of its divisors is an integer number (103397400).

Almost surely, 2^18561916800 is an apocalyptic number.

18561916800 is a gapful number since it is divisible by the number (10) 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 18561916800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39704601600).

18561916800 is an abundant number, since it is smaller than the sum of its proper divisors (60847286400).

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

18561916800 is a wasteful number, since it uses less digits than its factorization.

18561916800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 740 (or 717 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 45.

The spelling of 18561916800 in words is "eighteen billion, five hundred sixty-one million, nine hundred sixteen thousand, eight hundred".