165840211 has 4 divisors (see below), whose sum is σ = 165948552. Its totient is φ = 165731872.

The previous prime is 165840187. The next prime is 165840217. The reversal of 165840211 is 112048561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 112048561 = 419 ⋅267419.

It is a cyclic number.

It is not a de Polignac number, because 165840211 - 2⁹ = 165839699 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 165840211.

It is not an unprimeable number, because it can be changed into a prime (165840217) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 51841 + ... + 54946.

It is an arithmetic number, because the mean of its divisors is an integer number (41487138).

Almost surely, 2^165840211 is an apocalyptic number.

165840211 is a deficient number, since it is larger than the sum of its proper divisors (108341).

165840211 is a wasteful number, since it uses less digits than its factorization.

165840211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108340.

The product of its (nonzero) digits is 1920, while the sum is 28.

The square root of 165840211 is about 12877.8962179387. The cubic root of 165840211 is about 549.4100682901.

Adding to 165840211 its reverse (112048561), we get a palindrome (277888772).

The spelling of 165840211 in words is "one hundred sixty-five million, eight hundred forty thousand, two hundred eleven".