21831375665 has 32 divisors (see below), whose sum is σ = 28715299200. Its totient is φ = 15801984000.

The previous prime is 21831375641. The next prime is 21831375691. The reversal of 21831375665 is 56657313812.

It is not a de Polignac number, because 21831375665 - 2⁸ = 21831375409 is a prime.

It is a Smith number, since the sum of its digits (47) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18177065 + ... + 18178265.

It is an arithmetic number, because the mean of its divisors is an integer number (897353100).

Almost surely, 2^21831375665 is an apocalyptic number.

It is an amenable number.

21831375665 is a deficient number, since it is larger than the sum of its proper divisors (6883923535).

21831375665 is a wasteful number, since it uses less digits than its factorization.

21831375665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2513.

The product of its digits is 907200, while the sum is 47.

The spelling of 21831375665 in words is "twenty-one billion, eight hundred thirty-one million, three hundred seventy-five thousand, six hundred sixty-five".