21973566720 has 288 divisors, whose sum is σ = 80436142080. Its totient is φ = 5007974400.

The previous prime is 21973566707. The next prime is 21973566731. The reversal of 21973566720 is 2766537912.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 21973566720.

It is a congruent number.

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 31 ways as a sum of consecutive naturals, for example, 11261745 + ... + 11263695.

It is an arithmetic number, because the mean of its divisors is an integer number (279292160).

Almost surely, 2^21973566720 is an apocalyptic number.

21973566720 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 21973566720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40218071040).

21973566720 is an abundant number, since it is smaller than the sum of its proper divisors (58462575360).

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

21973566720 is a wasteful number, since it uses less digits than its factorization.

21973566720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2401 (or 2387 counting only the distinct ones).

The product of its (nonzero) digits is 952560, while the sum is 48.

The spelling of 21973566720 in words is "twenty-one billion, nine hundred seventy-three million, five hundred sixty-six thousand, seven hundred twenty".