21205594368 has 864 divisors, whose sum is σ = 80530329600. Its totient is φ = 5462360064.

The previous prime is 21205594363. The next prime is 21205594393. The reversal of 21205594368 is 86349550212.

21205594368 is a `hidden beast` number, since 2 + 1 + 20 + 5 + 594 + 36 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (864).

It is a super-3 number, since 3×21205594368³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21205594363) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 166973121 + ... + 166973247.

It is an arithmetic number, because the mean of its divisors is an integer number (93206400).

Almost surely, 2^21205594368 is an apocalyptic number.

21205594368 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 21205594368, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40265164800).

21205594368 is an abundant number, since it is smaller than the sum of its proper divisors (59324735232).

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

21205594368 is a wasteful number, since it uses less digits than its factorization.

21205594368 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212 (or 185 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 45.

The spelling of 21205594368 in words is "twenty-one billion, two hundred five million, five hundred ninety-four thousand, three hundred sixty-eight".