195909 has 16 divisors (see below), whose sum is σ = 314880. Its totient is φ = 105840.

The previous prime is 195907. The next prime is 195913. The reversal of 195909 is 909591.

195909 = T₁₃₄ + T₁₃₅ + ... + T₁₅₂.

195909 is nontrivially palindromic in base 12.

It is not a de Polignac number, because 195909 - 2¹ = 195907 is a prime.

It is an Ulam number.

195909 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 195909.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 195909.

It is not an unprimeable number, because it can be changed into a prime (195907) 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 15 ways as a sum of consecutive naturals, for example, 154 + ... + 644.

It is an arithmetic number, because the mean of its divisors is an integer number (19680).

2¹⁹⁵⁹⁰⁹ is an apocalyptic number.

195909 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

195909 is a deficient number, since it is larger than the sum of its proper divisors (118971).

195909 is a wasteful number, since it uses less digits than its factorization.

195909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 520.

The product of its (nonzero) digits is 3645, while the sum is 33.

The square root of 195909 is about 442.6160864677. The cubic root of 195909 is about 58.0788661566.

The spelling of 195909 in words is "one hundred ninety-five thousand, nine hundred nine".