21658204564 has 24 divisors (see below), whose sum is σ = 39581640000. Its totient is φ = 10349923584.

The previous prime is 21658204559. The next prime is 21658204637. The reversal of 21658204564 is 46540285612.

It is a self number, because there is not a number n which added to its sum of digits gives 21658204564.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20667 + ... + 209149.

It is an arithmetic number, because the mean of its divisors is an integer number (1649235000).

Almost surely, 2^21658204564 is an apocalyptic number.

It is an amenable number.

21658204564 is a deficient number, since it is larger than the sum of its proper divisors (17923435436).

21658204564 is a wasteful number, since it uses less digits than its factorization.

21658204564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189759 (or 189757 counting only the distinct ones).

The product of its (nonzero) digits is 460800, while the sum is 43.

The spelling of 21658204564 in words is "twenty-one billion, six hundred fifty-eight million, two hundred four thousand, five hundred sixty-four".