21243340800 has 864 divisors, whose sum is σ = 86444467200. Its totient is φ = 5109350400.

The previous prime is 21243340747. The next prime is 21243340819. The reversal of 21243340800 is 804334212.

21243340800 is a `hidden beast` number, since 2 + 1 + 243 + 340 + 80 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (864).

It is a Harshad number since it is a multiple of its sum of digits (27).

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, 167270337 + ... + 167270463.

Almost surely, 2^21243340800 is an apocalyptic number.

21243340800 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 21243340800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43222233600).

21243340800 is an abundant number, since it is smaller than the sum of its proper divisors (65201126400).

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

21243340800 is a wasteful number, since it uses less digits than its factorization.

21243340800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 190 (or 148 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 27.

The spelling of 21243340800 in words is "twenty-one billion, two hundred forty-three million, three hundred forty thousand, eight hundred".