209623 has 2 divisors, whose sum is σ = 209624. Its totient is φ = 209622.

The previous prime is 209621. The next prime is 209639. The reversal of 209623 is 326902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 209623 - 2¹ = 209621 is a prime.

Together with 209621, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 209594 and 209603.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (209621) 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 as a sum of consecutive naturals, namely, 104811 + 104812.

It is an arithmetic number, because the mean of its divisors is an integer number (104812).

2²⁰⁹⁶²³ is an apocalyptic number.

209623 is a deficient number, since it is larger than the sum of its proper divisors (1).

209623 is an equidigital number, since it uses as much as digits as its factorization.

209623 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 22.

The square root of 209623 is about 457.8460439930. The cubic root of 209623 is about 59.4036290376.

The spelling of 209623 in words is "two hundred nine thousand, six hundred twenty-three".