2165442665221 has 4 divisors (see below), whose sum is σ = 2362301089344. Its totient is φ = 1968584241100.

The previous prime is 2165442665179. The next prime is 2165442665233. The reversal of 2165442665221 is 1225662445612.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2165442665221 - 2¹¹ = 2165442663173 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2165442665521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 98429212045 + ... + 98429212066.

It is an arithmetic number, because the mean of its divisors is an integer number (590575272336).

Almost surely, 2^{2165442665221} is an apocalyptic number.

It is an amenable number.

2165442665221 is a deficient number, since it is larger than the sum of its proper divisors (196858424123).

2165442665221 is a wasteful number, since it uses less digits than its factorization.

2165442665221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196858424122.

The product of its digits is 1382400, while the sum is 46.

The spelling of 2165442665221 in words is "two trillion, one hundred sixty-five billion, four hundred forty-two million, six hundred sixty-five thousand, two hundred twenty-one".