21232747665 has 96 divisors (see below), whose sum is σ = 40001195520. Its totient is φ = 10382141952.

The previous prime is 21232747553. The next prime is 21232747687. The reversal of 21232747665 is 56674723212.

It is not a de Polignac number, because 21232747665 - 2⁹ = 21232747153 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 21232747665.

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 95 ways as a sum of consecutive naturals, for example, 6230392 + ... + 6233798.

It is an arithmetic number, because the mean of its divisors is an integer number (416679120).

Almost surely, 2^21232747665 is an apocalyptic number.

It is an amenable number.

21232747665 is a deficient number, since it is larger than the sum of its proper divisors (18768447855).

21232747665 is a wasteful number, since it uses less digits than its factorization.

21232747665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3671 (or 3668 counting only the distinct ones).

The product of its digits is 846720, while the sum is 45.

The spelling of 21232747665 in words is "twenty-one billion, two hundred thirty-two million, seven hundred forty-seven thousand, six hundred sixty-five".