21173799168 has 288 divisors, whose sum is σ = 64562601600. Its totient is φ = 6927482880.

The previous prime is 21173799137. The next prime is 21173799173. The reversal of 21173799168 is 86199737112.

It is a happy number.

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

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 33032128 + ... + 33032768.

It is an arithmetic number, because the mean of its divisors is an integer number (224175700).

Almost surely, 2^21173799168 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 21173799168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32281300800).

21173799168 is an abundant number, since it is smaller than the sum of its proper divisors (43388802432).

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

21173799168 is an frugal number, since it uses more digits than its factorization.

21173799168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 737 (or 705 counting only the distinct ones).

The product of its digits is 1143072, while the sum is 54.

The spelling of 21173799168 in words is "twenty-one billion, one hundred seventy-three million, seven hundred ninety-nine thousand, one hundred sixty-eight".