21168550368 has 288 divisors, whose sum is σ = 72720335520. Its totient is φ = 6047177472.

The previous prime is 21168550363. The next prime is 21168550369. The reversal of 21168550368 is 86305586112.

21168550368 is a `hidden beast` number, since 2 + 1 + 1 + 6 + 85 + 503 + 68 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21168550363) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3426130 + ... + 3432302.

It is an arithmetic number, because the mean of its divisors is an integer number (252501165).

Almost surely, 2^21168550368 is an apocalyptic number.

21168550368 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 21168550368, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36360167760).

21168550368 is an abundant number, since it is smaller than the sum of its proper divisors (51551785152).

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

21168550368 is an frugal number, since it uses more digits than its factorization.

21168550368 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6218 (or 6185 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 45.

It can be divided in two parts, 21168 and 550368, that added together give a square (571536 = 756²).

The spelling of 21168550368 in words is "twenty-one billion, one hundred sixty-eight million, five hundred fifty thousand, three hundred sixty-eight".