165192891261 has 4 divisors (see below), whose sum is σ = 220257188352. Its totient is φ = 110128594172.

The previous prime is 165192891251. The next prime is 165192891263. The reversal of 165192891261 is 162198291561.

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, and also an emirpimes, since its reverse is a distinct semiprime: 162198291561 = 3 ⋅54066097187.

It is a cyclic number.

It is not a de Polignac number, because 165192891261 - 2⁷ = 165192891133 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165192891263) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 27532148541 + ... + 27532148546.

It is an arithmetic number, because the mean of its divisors is an integer number (55064297088).

Almost surely, 2^165192891261 is an apocalyptic number.

It is an amenable number.

165192891261 is a deficient number, since it is larger than the sum of its proper divisors (55064297091).

165192891261 is an equidigital number, since it uses as much as digits as its factorization.

165192891261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55064297090.

The product of its digits is 466560, while the sum is 51.

The spelling of 165192891261 in words is "one hundred sixty-five billion, one hundred ninety-two million, eight hundred ninety-one thousand, two hundred sixty-one".