18945561600 has 792 divisors, whose sum is σ = 82203720768. Its totient is φ = 4069785600.

The previous prime is 18945561577. The next prime is 18945561623. The reversal of 18945561600 is 616554981.

18945561600 is a `hidden beast` number, since 1 + 8 + 94 + 556 + 1 + 6 + 0 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (18945561577) and next prime (18945561623).

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 71 ways as a sum of consecutive naturals, for example, 27417255 + ... + 27417945.

Almost surely, 2^18945561600 is an apocalyptic number.

18945561600 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 18945561600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41101860384).

18945561600 is an abundant number, since it is smaller than the sum of its proper divisors (63258159168).

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

18945561600 is a wasteful number, since it uses less digits than its factorization.

18945561600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 751 (or 725 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 45.

The spelling of 18945561600 in words is "eighteen billion, nine hundred forty-five million, five hundred sixty-one thousand, six hundred".