161905589 has 2 divisors, whose sum is σ = 161905590. Its totient is φ = 161905588.

The previous prime is 161905573. The next prime is 161905643. The reversal of 161905589 is 985509161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 154803364 + 7102225 = 12442^2 + 2665^2 .

It is a cyclic number.

It is not a de Polignac number, because 161905589 - 2⁴ = 161905573 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161905559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80952794 + 80952795.

It is an arithmetic number, because the mean of its divisors is an integer number (80952795).

Almost surely, 2^161905589 is an apocalyptic number.

It is an amenable number.

161905589 is a deficient number, since it is larger than the sum of its proper divisors (1).

161905589 is an equidigital number, since it uses as much as digits as its factorization.

161905589 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 97200, while the sum is 44.

The square root of 161905589 is about 12724.2127064899. The cubic root of 161905589 is about 545.0302583991.

The spelling of 161905589 in words is "one hundred sixty-one million, nine hundred five thousand, five hundred eighty-nine".