208109 has 4 divisors (see below), whose sum is σ = 227040. Its totient is φ = 189180.

The previous prime is 208099. The next prime is 208111. The reversal of 208109 is 901802.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 208109 - 2¹² = 204013 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (208129) 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, 9449 + ... + 9470.

It is an arithmetic number, because the mean of its divisors is an integer number (56760).

2²⁰⁸¹⁰⁹ is an apocalyptic number.

It is an amenable number.

208109 is a deficient number, since it is larger than the sum of its proper divisors (18931).

208109 is a wasteful number, since it uses less digits than its factorization.

208109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18930.

The product of its (nonzero) digits is 144, while the sum is 20.

The square root of 208109 is about 456.1896535433. The cubic root of 208109 is about 59.2602693067.

The spelling of 208109 in words is "two hundred eight thousand, one hundred nine".