181459981 has 2 divisors, whose sum is σ = 181459982. Its totient is φ = 181459980.

The previous prime is 181459939. The next prime is 181460011. The reversal of 181459981 is 189954181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 105247081 + 76212900 = 10259^2 + 8730^2 .

It is a cyclic number.

It is not a de Polignac number, because 181459981 - 2²¹ = 179362829 is a prime.

It is a super-2 number, since 2×181459981² = 65855449409040722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (181459381) 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, 90729990 + 90729991.

It is an arithmetic number, because the mean of its divisors is an integer number (90729991).

Almost surely, 2^181459981 is an apocalyptic number.

It is an amenable number.

181459981 is a deficient number, since it is larger than the sum of its proper divisors (1).

181459981 is an equidigital number, since it uses as much as digits as its factorization.

181459981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 103680, while the sum is 46.

The square root of 181459981 is about 13470.7082590337. The cubic root of 181459981 is about 566.1440582340.

The spelling of 181459981 in words is "one hundred eighty-one million, four hundred fifty-nine thousand, nine hundred eighty-one".