165105261091 has 4 divisors (see below), whose sum is σ = 165107549272. Its totient is φ = 165102972912.

The previous prime is 165105261049. The next prime is 165105261127. The reversal of 165105261091 is 190162501561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 190162501561 = 281 ⋅676734881.

It is a cyclic number.

It is not a de Polignac number, because 165105261091 - 2¹¹ = 165105259043 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 165105261091.

It is not an unprimeable number, because it can be changed into a prime (165105261031) 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, 1032210 + ... + 1181383.

It is an arithmetic number, because the mean of its divisors is an integer number (41276887318).

Almost surely, 2^165105261091 is an apocalyptic number.

165105261091 is a deficient number, since it is larger than the sum of its proper divisors (2288181).

165105261091 is an equidigital number, since it uses as much as digits as its factorization.

165105261091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2288180.

The product of its (nonzero) digits is 16200, while the sum is 37.

The spelling of 165105261091 in words is "one hundred sixty-five billion, one hundred five million, two hundred sixty-one thousand, ninety-one".