21297243168 has 144 divisors (see below), whose sum is σ = 63385882560. Its totient is φ = 7033671936.

The previous prime is 21297243109. The next prime is 21297243169. The reversal of 21297243168 is 86134279212.

21297243168 is a `hidden beast` number, since 21 + 297 + 24 + 316 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is not an unprimeable number, because it can be changed into a prime (21297243169) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 835021 + ... + 860147.

It is an arithmetic number, because the mean of its divisors is an integer number (440179740).

Almost surely, 2^21297243168 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 21297243168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31692941280).

21297243168 is an abundant number, since it is smaller than the sum of its proper divisors (42088639392).

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

21297243168 is a wasteful number, since it uses less digits than its factorization.

21297243168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25261 (or 25241 counting only the distinct ones).

The product of its digits is 290304, while the sum is 45.

The spelling of 21297243168 in words is "twenty-one billion, two hundred ninety-seven million, two hundred forty-three thousand, one hundred sixty-eight".