21353586768 has 200 divisors, whose sum is σ = 64655236800. Its totient is φ = 6791026176.

The previous prime is 21353586757. The next prime is 21353586773. The reversal of 21353586768 is 86768535312.

21353586768 is a `hidden beast` number, since 2 + 1 + 3 + 53 + 586 + 7 + 6 + 8 = 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 polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 16960123 + ... + 16961381.

It is an arithmetic number, because the mean of its divisors is an integer number (323276184).

Almost surely, 2^21353586768 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21353586768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32327618400).

21353586768 is an abundant number, since it is smaller than the sum of its proper divisors (43301650032).

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

21353586768 is a wasteful number, since it uses less digits than its factorization.

21353586768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1871 (or 1856 counting only the distinct ones).

The product of its digits is 7257600, while the sum is 54.

The spelling of 21353586768 in words is "twenty-one billion, three hundred fifty-three million, five hundred eighty-six thousand, seven hundred sixty-eight".