18991540800 has 336 divisors, whose sum is σ = 69448680000. Its totient is φ = 5048524800.

The previous prime is 18991540781. The next prime is 18991540817. The reversal of 18991540800 is 804519981.

18991540800 is a `hidden beast` number, since 18 + 9 + 91 + 540 + 8 + 0 + 0 = 666.

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 (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 21556360 + ... + 21557240.

It is an arithmetic number, because the mean of its divisors is an integer number (206692500).

Almost surely, 2^18991540800 is an apocalyptic number.

18991540800 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 18991540800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34724340000).

18991540800 is an abundant number, since it is smaller than the sum of its proper divisors (50457139200).

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

18991540800 is a wasteful number, since it uses less digits than its factorization.

18991540800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1411 (or 1390 counting only the distinct ones).

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

The spelling of 18991540800 in words is "eighteen billion, nine hundred ninety-one million, five hundred forty thousand, eight hundred".