195689 has 4 divisors (see below), whose sum is σ = 210756. Its totient is φ = 180624.

The previous prime is 195677. The next prime is 195691. The reversal of 195689 is 986591.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 986591 = 281 ⋅3511.

It can be written as a sum of positive squares in 2 ways, for example, as 115600 + 80089 = 340^2 + 283^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-195689 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (195659) 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 3 ways as a sum of consecutive naturals, for example, 7514 + ... + 7539.

It is an arithmetic number, because the mean of its divisors is an integer number (52689).

195689 is a Friedman number, since it can be written as 8^5*6-919, using all its digits and the basic arithmetic operations.

2¹⁹⁵⁶⁸⁹ is an apocalyptic number.

It is an amenable number.

195689 is a deficient number, since it is larger than the sum of its proper divisors (15067).

195689 is a wasteful number, since it uses less digits than its factorization.

195689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15066.

The product of its digits is 19440, while the sum is 38.

The square root of 195689 is about 442.3674942850. The cubic root of 195689 is about 58.0571177319.

The spelling of 195689 in words is "one hundred ninety-five thousand, six hundred eighty-nine".