21786605568 has 576 divisors, whose sum is σ = 80133580800. Its totient is φ = 5547294720.

The previous prime is 21786605567. The next prime is 21786605579. The reversal of 21786605568 is 86550668712.

21786605568 is a `hidden beast` number, since 2 + 1 + 7 + 86 + 6 + 0 + 556 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (576).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21786605563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 51996463 + ... + 51996881.

It is an arithmetic number, because the mean of its divisors is an integer number (139120800).

Almost surely, 2^21786605568 is an apocalyptic number.

21786605568 is a gapful number since it is divisible by the number (28) 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 21786605568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40066790400).

21786605568 is an abundant number, since it is smaller than the sum of its proper divisors (58346975232).

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

21786605568 is a wasteful number, since it uses less digits than its factorization.

21786605568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 498 (or 475 counting only the distinct ones).

The product of its (nonzero) digits is 4838400, while the sum is 54.

The spelling of 21786605568 in words is "twenty-one billion, seven hundred eighty-six million, six hundred five thousand, five hundred sixty-eight".