209923 has 4 divisors (see below), whose sum is σ = 239920. Its totient is φ = 179928.

The previous prime is 209917. The next prime is 209927. The reversal of 209923 is 329902.

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

It is not a de Polignac number, because 209923 - 2¹³ = 201731 is a prime.

It is a d-powerful number, because it can be written as 2³ + 0 + 9⁵ + 9⁵ + 2¹⁵ + 3¹⁰ .

It is a Duffinian number.

It is a plaindrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (209927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14988 + ... + 15001.

It is an arithmetic number, because the mean of its divisors is an integer number (59980).

2²⁰⁹⁹²³ is an apocalyptic number.

209923 is a deficient number, since it is larger than the sum of its proper divisors (29997).

209923 is an equidigital number, since it uses as much as digits as its factorization.

209923 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29996.

The product of its (nonzero) digits is 972, while the sum is 25.

The square root of 209923 is about 458.1735479052. The cubic root of 209923 is about 59.4319538460.

The spelling of 209923 in words is "two hundred nine thousand, nine hundred twenty-three".