181997089 has 2 divisors, whose sum is σ = 181997090. Its totient is φ = 181997088.

The previous prime is 181997083. The next prime is 181997111. The reversal of 181997089 is 980799181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 107744400 + 74252689 = 10380^2 + 8617^2 .

It is a cyclic number.

It is not a de Polignac number, because 181997089 - 2¹⁹ = 181472801 is a prime.

It is not a weakly prime, because it can be changed into another prime (181997083) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90998544 + 90998545.

It is an arithmetic number, because the mean of its divisors is an integer number (90998545).

Almost surely, 2^181997089 is an apocalyptic number.

It is an amenable number.

181997089 is a deficient number, since it is larger than the sum of its proper divisors (1).

181997089 is an equidigital number, since it uses as much as digits as its factorization.

181997089 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 326592, while the sum is 52.

The square root of 181997089 is about 13490.6296739626. The cubic root of 181997089 is about 566.7020894043.

The spelling of 181997089 in words is "one hundred eighty-one million, nine hundred ninety-seven thousand, eighty-nine".