18921815918460 has 2304 divisors, whose sum is σ = 81191732428800. Its totient is φ = 3656994324480.

The previous prime is 18921815918353. The next prime is 18921815918477. The reversal of 18921815918460 is 6481951812981.

18921815918460 is a `hidden beast` number, since 1 + 8 + 9 + 2 + 1 + 8 + 159 + 18 + 460 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 767 ways as a sum of consecutive naturals, for example, 16410941244 + ... + 16410942396.

It is an arithmetic number, because the mean of its divisors is an integer number (35239467200).

Almost surely, 2^{18921815918460} is an apocalyptic number.

18921815918460 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 18921815918460, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40595866214400).

18921815918460 is an abundant number, since it is smaller than the sum of its proper divisors (62269916510340).

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

18921815918460 is a wasteful number, since it uses less digits than its factorization.

18921815918460 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1260 (or 1233 counting only the distinct ones).

The product of its (nonzero) digits is 9953280, while the sum is 63.

The spelling of 18921815918460 in words is "eighteen trillion, nine hundred twenty-one billion, eight hundred fifteen million, nine hundred eighteen thousand, four hundred sixty".