21652591968 has 216 divisors, whose sum is σ = 71773058448. Its totient is φ = 6173895168.

The previous prime is 21652591951. The next prime is 21652592021. The reversal of 21652591968 is 86919525612.

21652591968 is a `hidden beast` number, since 21 + 6 + 525 + 9 + 1 + 96 + 8 = 666.

It is a super-2 number, since 2×21652591968² (a number of 21 digits) contains 22 as substring.

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 35 ways as a sum of consecutive naturals, for example, 8649405 + ... + 8651907.

It is an arithmetic number, because the mean of its divisors is an integer number (332282678).

Almost surely, 2^21652591968 is an apocalyptic number.

21652591968 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 21652591968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35886529224).

21652591968 is an abundant number, since it is smaller than the sum of its proper divisors (50120466480).

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

21652591968 is a wasteful number, since it uses less digits than its factorization.

21652591968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3146 (or 3128 counting only the distinct ones).

The product of its digits is 2332800, while the sum is 54.

The spelling of 21652591968 in words is "twenty-one billion, six hundred fifty-two million, five hundred ninety-one thousand, nine hundred sixty-eight".