181442665 has 4 divisors (see below), whose sum is σ = 217731204. Its totient is φ = 145154128.

The previous prime is 181442627. The next prime is 181442669. The reversal of 181442665 is 566244181.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 566244181 = 59 ⋅9597359.

It can be written as a sum of positive squares in 2 ways, for example, as 125731369 + 55711296 = 11213^2 + 7464^2 .

It is a cyclic number.

It is not a de Polignac number, because 181442665 - 2⁷ = 181442537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (181442669) 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, 18144262 + ... + 18144271.

It is an arithmetic number, because the mean of its divisors is an integer number (54432801).

Almost surely, 2^181442665 is an apocalyptic number.

It is an amenable number.

181442665 is a deficient number, since it is larger than the sum of its proper divisors (36288539).

181442665 is an equidigital number, since it uses as much as digits as its factorization.

181442665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36288538.

The product of its digits is 46080, while the sum is 37.

The square root of 181442665 is about 13470.0655158021. The cubic root of 181442665 is about 566.1260493736.

The spelling of 181442665 in words is "one hundred eighty-one million, four hundred forty-two thousand, six hundred sixty-five".