209609 has 4 divisors (see below), whose sum is σ = 210960. Its totient is φ = 208260.

The previous prime is 209597. The next prime is 209621. The reversal of 209609 is 906902.

209609 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, and also an emirpimes, since its reverse is a distinct semiprime: 906902 = 2 ⋅453451.

It is an interprime number because it is at equal distance from previous prime (209597) and next prime (209621).

It is a cyclic number.

It is not a de Polignac number, because 209609 - 2⁸ = 209353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (209639) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 407 + ... + 764.

It is an arithmetic number, because the mean of its divisors is an integer number (52740).

2²⁰⁹⁶⁰⁹ is an apocalyptic number.

It is an amenable number.

209609 is a deficient number, since it is larger than the sum of its proper divisors (1351).

209609 is a wasteful number, since it uses less digits than its factorization.

209609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1350.

The product of its (nonzero) digits is 972, while the sum is 26.

The square root of 209609 is about 457.8307547555. The cubic root of 209609 is about 59.4023065534.

It can be divided in two parts, 209 and 609, that added together give a palindrome (818).

The spelling of 209609 in words is "two hundred nine thousand, six hundred nine".