18821664338400 has 2016 divisors, whose sum is σ = 87310902744576. Its totient is φ = 3846320640000.

The previous prime is 18821664338341. The next prime is 18821664338497. The reversal of 18821664338400 is 483346612881.

It is a happy number.

18821664338400 is a `hidden beast` number, since 1 + 8 + 8 + 2 + 166 + 43 + 38 + 400 = 666.

It is a tau number, because it is divible by the number of its divisors (2016).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 335 ways as a sum of consecutive naturals, for example, 2739286965 + ... + 2739293835.

It is an arithmetic number, because the mean of its divisors is an integer number (43308979536).

Almost surely, 2^{18821664338400} is an apocalyptic number.

18821664338400 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 18821664338400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43655451372288).

18821664338400 is an abundant number, since it is smaller than the sum of its proper divisors (68489238406176).

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

18821664338400 is a wasteful number, since it uses less digits than its factorization.

18821664338400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6988 (or 6960 counting only the distinct ones).

The product of its (nonzero) digits is 5308416, while the sum is 54.

The spelling of 18821664338400 in words is "eighteen trillion, eight hundred twenty-one billion, six hundred sixty-four million, three hundred thirty-eight thousand, four hundred".