209929 has 2 divisors, whose sum is σ = 209930. Its totient is φ = 209928.

The previous prime is 209927. The next prime is 209939. The reversal of 209929 is 929902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 204304 + 5625 = 452^2 + 75^2 .

It is a cyclic number.

It is not a de Polignac number, because 209929 - 2¹ = 209927 is a prime.

Together with 209927, it forms a pair of twin primes.

209929 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 209929.

It is not a weakly prime, because it can be changed into another 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 as a sum of consecutive naturals, namely, 104964 + 104965.

It is an arithmetic number, because the mean of its divisors is an integer number (104965).

2²⁰⁹⁹²⁹ is an apocalyptic number.

It is an amenable number.

209929 is a deficient number, since it is larger than the sum of its proper divisors (1).

209929 is an equidigital number, since it uses as much as digits as its factorization.

209929 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2916, while the sum is 31.

The square root of 209929 is about 458.1800955956. The cubic root of 209929 is about 59.4325200669.

The spelling of 209929 in words is "two hundred nine thousand, nine hundred twenty-nine".