21897320695665 has 16 divisors (see below), whose sum is σ = 35035775650176. Its totient is φ = 11678550192000.

The previous prime is 21897320695513. The next prime is 21897320695709. The reversal of 21897320695665 is 56659602379812.

It is not a de Polignac number, because 21897320695665 - 2²⁰ = 21897319647089 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21897320695665.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11335860 + ... + 13126170.

It is an arithmetic number, because the mean of its divisors is an integer number (2189735978136).

Almost surely, 2^{21897320695665} is an apocalyptic number.

It is an amenable number.

21897320695665 is a deficient number, since it is larger than the sum of its proper divisors (13138454954511).

21897320695665 is a wasteful number, since it uses less digits than its factorization.

21897320695665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2605720.

The product of its (nonzero) digits is 293932800, while the sum is 69.

The spelling of 21897320695665 in words is "twenty-one trillion, eight hundred ninety-seven billion, three hundred twenty million, six hundred ninety-five thousand, six hundred sixty-five".