21165559372 has 24 divisors (see below), whose sum is σ = 37233319536. Its totient is φ = 10527599808.

The previous prime is 21165559369. The next prime is 21165559417. The reversal of 21165559372 is 27395556112.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 643798 + ... + 675874.

It is an arithmetic number, because the mean of its divisors is an integer number (1551388314).

Almost surely, 2^21165559372 is an apocalyptic number.

It is an amenable number.

21165559372 is a deficient number, since it is larger than the sum of its proper divisors (16067760164).

21165559372 is a wasteful number, since it uses less digits than its factorization.

21165559372 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32937 (or 32935 counting only the distinct ones).

The product of its digits is 567000, while the sum is 46.

The spelling of 21165559372 in words is "twenty-one billion, one hundred sixty-five million, five hundred fifty-nine thousand, three hundred seventy-two".