195509 has 4 divisors (see below), whose sum is σ = 196716. Its totient is φ = 194304.

The previous prime is 195497. The next prime is 195511. The reversal of 195509 is 905591.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 905591 = 59 ⋅15349.

It can be written as a sum of positive squares in 2 ways, for example, as 14884 + 180625 = 122^2 + 425^2 .

It is a cyclic number.

It is not a de Polignac number, because 195509 - 2⁴ = 195493 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (195539) 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 in 3 ways as a sum of consecutive naturals, for example, 314 + ... + 699.

It is an arithmetic number, because the mean of its divisors is an integer number (49179).

2¹⁹⁵⁵⁰⁹ is an apocalyptic number.

It is an amenable number.

195509 is a deficient number, since it is larger than the sum of its proper divisors (1207).

195509 is a wasteful number, since it uses less digits than its factorization.

195509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1206.

The product of its (nonzero) digits is 2025, while the sum is 29.

The square root of 195509 is about 442.1639967252. The cubic root of 195509 is about 58.0393114389.

The spelling of 195509 in words is "one hundred ninety-five thousand, five hundred nine".