21204892800 has 1920 divisors, whose sum is σ = 102843417600. Its totient is φ = 4180377600.

The previous prime is 21204892789. The next prime is 21204892853. The reversal of 21204892800 is 829840212.

It is a tau number, because it is divible by the number of its divisors (1920).

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

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 239 ways as a sum of consecutive naturals, for example, 684028785 + ... + 684028815.

It is an arithmetic number, because the mean of its divisors is an integer number (53564280).

Almost surely, 2^21204892800 is an apocalyptic number.

21204892800 is a gapful number since it is divisible by the number (20) 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 21204892800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (51421708800).

21204892800 is an abundant number, since it is smaller than the sum of its proper divisors (81638524800).

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

21204892800 is a wasteful number, since it uses less digits than its factorization.

21204892800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116 (or 90 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The spelling of 21204892800 in words is "twenty-one billion, two hundred four million, eight hundred ninety-two thousand, eight hundred".