181802161 has 2 divisors, whose sum is σ = 181802162. Its totient is φ = 181802160.

The previous prime is 181802123. The next prime is 181802171. The reversal of 181802161 is 161208181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 180633600 + 1168561 = 13440^2 + 1081^2 .

It is an emirp because it is prime and its reverse (161208181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 181802161 - 2²³ = 173413553 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (181802111) 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 as a sum of consecutive naturals, namely, 90901080 + 90901081.

It is an arithmetic number, because the mean of its divisors is an integer number (90901081).

Almost surely, 2^181802161 is an apocalyptic number.

It is an amenable number.

181802161 is a deficient number, since it is larger than the sum of its proper divisors (1).

181802161 is an equidigital number, since it uses as much as digits as its factorization.

181802161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 768, while the sum is 28.

The square root of 181802161 is about 13483.4031683400. The cubic root of 181802161 is about 566.4996950194.

The spelling of 181802161 in words is "one hundred eighty-one million, eight hundred two thousand, one hundred sixty-one".