161265091 has 4 divisors (see below), whose sum is σ = 173670112. Its totient is φ = 148860072.

The previous prime is 161265079. The next prime is 161265133. The reversal of 161265091 is 190562161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 190562161 = 29 ⋅6571109.

It is a cyclic number.

It is not a de Polignac number, because 161265091 - 2⁵ = 161265059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161265031) 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, 6202491 + ... + 6202516.

It is an arithmetic number, because the mean of its divisors is an integer number (43417528).

Almost surely, 2^161265091 is an apocalyptic number.

161265091 is a deficient number, since it is larger than the sum of its proper divisors (12405021).

161265091 is a wasteful number, since it uses less digits than its factorization.

161265091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12405020.

The product of its (nonzero) digits is 3240, while the sum is 31.

The square root of 161265091 is about 12699.0192928431. The cubic root of 161265091 is about 544.3105959073.

The spelling of 161265091 in words is "one hundred sixty-one million, two hundred sixty-five thousand, ninety-one".