209849 has 4 divisors (see below), whose sum is σ = 211236. Its totient is φ = 208464.

The previous prime is 209837. The next prime is 209851. The reversal of 209849 is 948902.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 94249 + 115600 = 307^2 + 340^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-209849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (209809) 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, 434 + ... + 779.

It is an arithmetic number, because the mean of its divisors is an integer number (52809).

2²⁰⁹⁸⁴⁹ is an apocalyptic number.

It is an amenable number.

209849 is a deficient number, since it is larger than the sum of its proper divisors (1387).

209849 is a wasteful number, since it uses less digits than its factorization.

209849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1386.

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 209849 is about 458.0927853612. The cubic root of 209849 is about 59.4249695685.

The spelling of 209849 in words is "two hundred nine thousand, eight hundred forty-nine".