181162381 has 4 divisors (see below), whose sum is σ = 181209052. Its totient is φ = 181115712.

The previous prime is 181162367. The next prime is 181162403. The reversal of 181162381 is 183261181.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 183261181 = 31 ⋅5911651.

It can be written as a sum of positive squares in 2 ways, for example, as 78322500 + 102839881 = 8850^2 + 10141^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-181162381 is a prime.

It is a super-2 number, since 2×181162381² = 65639616579178322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (181162781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16926 + ... + 25471.

It is an arithmetic number, because the mean of its divisors is an integer number (45302263).

Almost surely, 2^181162381 is an apocalyptic number.

It is an amenable number.

181162381 is a deficient number, since it is larger than the sum of its proper divisors (46671).

181162381 is an equidigital number, since it uses as much as digits as its factorization.

181162381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46670.

The product of its digits is 2304, while the sum is 31.

The square root of 181162381 is about 13459.6575365052. The cubic root of 181162381 is about 565.8343909428.

The spelling of 181162381 in words is "one hundred eighty-one million, one hundred sixty-two thousand, three hundred eighty-one".