21806765568 has 600 divisors, whose sum is σ = 77183033928. Its totient is φ = 6145155072.

The previous prime is 21806765531. The next prime is 21806765573. The reversal of 21806765568 is 86556760812.

21806765568 is a `hidden beast` number, since 2 + 1 + 8 + 0 + 6 + 76 + 5 + 568 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

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 59 ways as a sum of consecutive naturals, for example, 298722780 + ... + 298722852.

Almost surely, 2^21806765568 is an apocalyptic number.

21806765568 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 21806765568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38591516964).

21806765568 is an abundant number, since it is smaller than the sum of its proper divisors (55376268360).

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

21806765568 is an frugal number, since it uses more digits than its factorization.

21806765568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134 (or 85 counting only the distinct ones).

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

The spelling of 21806765568 in words is "twenty-one billion, eight hundred six million, seven hundred sixty-five thousand, five hundred sixty-eight".