181045981 has 2 divisors, whose sum is σ = 181045982. Its totient is φ = 181045980.

The previous prime is 181045979. The next prime is 181045999. The reversal of 181045981 is 189540181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 174108025 + 6937956 = 13195^2 + 2634^2 .

It is a cyclic number.

It is not a de Polignac number, because 181045981 - 2¹ = 181045979 is a prime.

It is a super-2 number, since 2×181045981² = 65555294472504722, which contains 22 as substring.

Together with 181045979, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 181045981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (181045901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90522990 + 90522991.

It is an arithmetic number, because the mean of its divisors is an integer number (90522991).

Almost surely, 2^181045981 is an apocalyptic number.

It is an amenable number.

181045981 is a deficient number, since it is larger than the sum of its proper divisors (1).

181045981 is an equidigital number, since it uses as much as digits as its factorization.

181045981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11520, while the sum is 37.

The square root of 181045981 is about 13455.3328089646. The cubic root of 181045981 is about 565.7131788128.

The spelling of 181045981 in words is "one hundred eighty-one million, forty-five thousand, nine hundred eighty-one".