21155983200 has 864 divisors, whose sum is σ = 90815437440. Its totient is φ = 4567449600.

The previous prime is 21155983193. The next prime is 21155983213. The reversal of 21155983200 is 238955112.

21155983200 is a `hidden beast` number, since 2 + 1 + 1 + 559 + 83 + 20 + 0 = 666.

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 polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 25581187 + ... + 25582013.

It is an arithmetic number, because the mean of its divisors is an integer number (105110460).

Almost surely, 2^21155983200 is an apocalyptic number.

21155983200 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 21155983200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45407718720).

21155983200 is an abundant number, since it is smaller than the sum of its proper divisors (69659454240).

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

21155983200 is a wasteful number, since it uses less digits than its factorization.

21155983200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 900 (or 884 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 36.

The spelling of 21155983200 in words is "twenty-one billion, one hundred fifty-five million, nine hundred eighty-three thousand, two hundred".