21681097200 has 960 divisors, whose sum is σ = 94794885120. Its totient is φ = 4598415360.

The previous prime is 21681097199. The next prime is 21681097211. The reversal of 21681097200 is 279018612.

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 191 ways as a sum of consecutive naturals, for example, 64335432 + ... + 64335768.

It is an arithmetic number, because the mean of its divisors is an integer number (98744672).

Almost surely, 2^21681097200 is an apocalyptic number.

21681097200 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 21681097200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47397442560).

21681097200 is an abundant number, since it is smaller than the sum of its proper divisors (73113787920).

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

21681097200 is a wasteful number, since it uses less digits than its factorization.

21681097200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 431 (or 414 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 36.

The spelling of 21681097200 in words is "twenty-one billion, six hundred eighty-one million, ninety-seven thousand, two hundred".