2166323240565 has 192 divisors, whose sum is σ = 4333461350400. Its totient is φ = 1029377859840.

The previous prime is 2166323240551. The next prime is 2166323240647. The reversal of 2166323240565 is 5650423236612.

2166323240565 is a `hidden beast` number, since 2 + 1 + 6 + 6 + 3 + 232 + 405 + 6 + 5 = 666.

It is not a de Polignac number, because 2166323240565 - 2²⁵ = 2166289686133 is a prime.

It is a super-2 number, since 2×2166323240565² (a number of 25 digits) contains 22 as substring.

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

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 2166323240565.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 178189467 + ... + 178201623.

It is an arithmetic number, because the mean of its divisors is an integer number (22570111200).

Almost surely, 2^{2166323240565} is an apocalyptic number.

It is an amenable number.

2166323240565 is an abundant number, since it is smaller than the sum of its proper divisors (2167138109835).

2166323240565 is a wasteful number, since it uses less digits than its factorization.

2166323240565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12454 (or 12442 counting only the distinct ones).

The product of its (nonzero) digits is 1555200, while the sum is 45.

The spelling of 2166323240565 in words is "two trillion, one hundred sixty-six billion, three hundred twenty-three million, two hundred forty thousand, five hundred sixty-five".