21681697168 has 20 divisors (see below), whose sum is σ = 42011259520. Its totient is φ = 10840081824.

The previous prime is 21681697159. The next prime is 21681697171. The reversal of 21681697168 is 86179618612.

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 3 ways as a sum of consecutive naturals, for example, 236521 + ... + 315127.

It is an arithmetic number, because the mean of its divisors is an integer number (2100562976).

Almost surely, 2^21681697168 is an apocalyptic number.

It is an amenable number.

21681697168 is a deficient number, since it is larger than the sum of its proper divisors (20329562352).

21681697168 is a wasteful number, since it uses less digits than its factorization.

21681697168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95854 (or 95848 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 55.

The spelling of 21681697168 in words is "twenty-one billion, six hundred eighty-one million, six hundred ninety-seven thousand, one hundred sixty-eight".