21089405568 has 576 divisors, whose sum is σ = 73305237600. Its totient is φ = 5350625280.

The previous prime is 21089405567. The next prime is 21089405609. The reversal of 21089405568 is 86550498012.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is not an unprimeable number, because it can be changed into a prime (21089405563) by changing a digit.

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 71 ways as a sum of consecutive naturals, for example, 134327346 + ... + 134327502.

Almost surely, 2^21089405568 is an apocalyptic number.

21089405568 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 21089405568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36652618800).

21089405568 is an abundant number, since it is smaller than the sum of its proper divisors (52215832032).

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

21089405568 is a wasteful number, since it uses less digits than its factorization.

21089405568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 269 (or 239 counting only the distinct ones).

The product of its (nonzero) digits is 691200, while the sum is 48.

The spelling of 21089405568 in words is "twenty-one billion, eighty-nine million, four hundred five thousand, five hundred sixty-eight".