181985166589 has 2 divisors, whose sum is σ = 181985166590. Its totient is φ = 181985166588.

The previous prime is 181985166569. The next prime is 181985166599. The reversal of 181985166589 is 985661589181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 146025629689 + 35959536900 = 382133^2 + 189630^2 .

It is a cyclic number.

It is not a de Polignac number, because 181985166589 - 2¹¹ = 181985164541 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (181985166569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90992583294 + 90992583295.

It is an arithmetic number, because the mean of its divisors is an integer number (90992583295).

Almost surely, 2^181985166589 is an apocalyptic number.

It is an amenable number.

181985166589 is a deficient number, since it is larger than the sum of its proper divisors (1).

181985166589 is an equidigital number, since it uses as much as digits as its factorization.

181985166589 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 37324800, while the sum is 67.

The spelling of 181985166589 in words is "one hundred eighty-one billion, nine hundred eighty-five million, one hundred sixty-six thousand, five hundred eighty-nine".