21528935568 has 400 divisors, whose sum is σ = 76520400000. Its totient is φ = 5825094912.

The previous prime is 21528935539. The next prime is 21528935569. The reversal of 21528935568 is 86553982512.

It is a happy number.

21528935568 is a `hidden beast` number, since 2 + 1 + 5 + 2 + 89 + 3 + 556 + 8 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (21528935569) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 8444758 + ... + 8447306.

It is an arithmetic number, because the mean of its divisors is an integer number (191301000).

Almost surely, 2^21528935568 is an apocalyptic number.

21528935568 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 21528935568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38260200000).

21528935568 is an abundant number, since it is smaller than the sum of its proper divisors (54991464432).

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

21528935568 is a wasteful number, since it uses less digits than its factorization.

21528935568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2609 (or 2580 counting only the distinct ones).

The product of its digits is 5184000, while the sum is 54.

The spelling of 21528935568 in words is "twenty-one billion, five hundred twenty-eight million, nine hundred thirty-five thousand, five hundred sixty-eight".