21564165424 has 10 divisors (see below), whose sum is σ = 41780570540. Its totient is φ = 10782082704.

The previous prime is 21564165383. The next prime is 21564165431. The reversal of 21564165424 is 42456146512.

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, 673880154 + ... + 673880185.

It is an arithmetic number, because the mean of its divisors is an integer number (4178057054).

Almost surely, 2^21564165424 is an apocalyptic number.

It is an amenable number.

21564165424 is a deficient number, since it is larger than the sum of its proper divisors (20216405116).

21564165424 is a wasteful number, since it uses less digits than its factorization.

21564165424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1347760347 (or 1347760341 counting only the distinct ones).

The product of its digits is 230400, while the sum is 40.

The spelling of 21564165424 in words is "twenty-one billion, five hundred sixty-four million, one hundred sixty-five thousand, four hundred twenty-four".