21605367168 has 896 divisors, whose sum is σ = 83908823040. Its totient is φ = 5374771200.

The previous prime is 21605367149. The next prime is 21605367181. The reversal of 21605367168 is 86176350612.

21605367168 is a `hidden beast` number, since 2 + 1 + 605 + 36 + 7 + 1 + 6 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (896).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 222735696 + ... + 222735792.

It is an arithmetic number, because the mean of its divisors is an integer number (93648240).

Almost surely, 2^21605367168 is an apocalyptic number.

21605367168 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 21605367168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41954411520).

21605367168 is an abundant number, since it is smaller than the sum of its proper divisors (62303455872).

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

21605367168 is an equidigital number, since it uses as much as digits as its factorization.

21605367168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178 (or 151 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The spelling of 21605367168 in words is "twenty-one billion, six hundred five million, three hundred sixty-seven thousand, one hundred sixty-eight".