189909 has 6 divisors (see below), whose sum is σ = 274326. Its totient is φ = 126600.

The previous prime is 189901. The next prime is 189913. The reversal of 189909 is 909981.

It can be written as a sum of positive squares in only one way, i.e., 140625 + 49284 = 375^2 + 222^2 .

It is not a de Polignac number, because 189909 - 2³ = 189901 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (189901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 10542 + ... + 10559.

It is an arithmetic number, because the mean of its divisors is an integer number (45721).

2¹⁸⁹⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

189909 is a deficient number, since it is larger than the sum of its proper divisors (84417).

189909 is a wasteful number, since it uses less digits than its factorization.

189909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21107 (or 21104 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 36.

The square root of 189909 is about 435.7854976935. The cubic root of 189909 is about 57.4797912600.

The spelling of 189909 in words is "one hundred eighty-nine thousand, nine hundred nine".