21668316584 has 8 divisors (see below), whose sum is σ = 40628093610. Its totient is φ = 10834158288.

The previous prime is 21668316499. The next prime is 21668316617. The reversal of 21668316584 is 48561386612.

It can be written as a sum of positive squares in only one way, i.e., 14840599684 + 6827716900 = 121822^2 + 82630^2 .

It is a tau number, because it is divible by the number of its divisors (8).

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 as a sum of consecutive naturals, namely, 1354269779 + ... + 1354269794.

Almost surely, 2^21668316584 is an apocalyptic number.

It is an amenable number.

21668316584 is a deficient number, since it is larger than the sum of its proper divisors (18959777026).

21668316584 is a wasteful number, since it uses less digits than its factorization.

21668316584 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2708539579 (or 2708539575 counting only the distinct ones).

The product of its digits is 1658880, while the sum is 50.

The spelling of 21668316584 in words is "twenty-one billion, six hundred sixty-eight million, three hundred sixteen thousand, five hundred eighty-four".