181261085 has 4 divisors (see below), whose sum is σ = 217513308. Its totient is φ = 145008864.

The previous prime is 181261081. The next prime is 181261133. The reversal of 181261085 is 580162181.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 580162181 = 8761 ⋅66221.

It can be written as a sum of positive squares in 2 ways, for example, as 112487236 + 68773849 = 10606^2 + 8293^2 .

It is a cyclic number.

It is not a de Polignac number, because 181261085 - 2² = 181261081 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (181261081) 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, 18126104 + ... + 18126113.

It is an arithmetic number, because the mean of its divisors is an integer number (54378327).

Almost surely, 2^181261085 is an apocalyptic number.

It is an amenable number.

181261085 is a deficient number, since it is larger than the sum of its proper divisors (36252223).

181261085 is an equidigital number, since it uses as much as digits as its factorization.

181261085 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36252222.

The product of its (nonzero) digits is 3840, while the sum is 32.

The square root of 181261085 is about 13463.3236981066. The cubic root of 181261085 is about 565.9371348226.

The spelling of 181261085 in words is "one hundred eighty-one million, two hundred sixty-one thousand, eighty-five".