181998497 has 2 divisors, whose sum is σ = 181998498. Its totient is φ = 181998496.

The previous prime is 181998469. The next prime is 181998521. The reversal of 181998497 is 794899181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 176597521 + 5400976 = 13289^2 + 2324^2 .

It is a cyclic number.

It is not a de Polignac number, because 181998497 - 2⁶ = 181998433 is a prime.

It is not a weakly prime, because it can be changed into another prime (181998407) 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, 90999248 + 90999249.

It is an arithmetic number, because the mean of its divisors is an integer number (90999249).

Almost surely, 2^181998497 is an apocalyptic number.

It is an amenable number.

181998497 is a deficient number, since it is larger than the sum of its proper divisors (1).

181998497 is an equidigital number, since it uses as much as digits as its factorization.

181998497 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1306368, while the sum is 56.

The square root of 181998497 is about 13490.6818582309. The cubic root of 181998497 is about 566.7035508095.

The spelling of 181998497 in words is "one hundred eighty-one million, nine hundred ninety-eight thousand, four hundred ninety-seven".