209329921 has 4 divisors (see below), whose sum is σ = 209542144. Its totient is φ = 209117700.

The previous prime is 209329919. The next prime is 209329931. The reversal of 209329921 is 129923902.

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.

It is a cyclic number.

It is not a de Polignac number, because 209329921 - 2¹ = 209329919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (209329931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 104625 + ... + 106606.

It is an arithmetic number, because the mean of its divisors is an integer number (52385536).

Almost surely, 2^209329921 is an apocalyptic number.

It is an amenable number.

209329921 is a deficient number, since it is larger than the sum of its proper divisors (212223).

209329921 is an equidigital number, since it uses as much as digits as its factorization.

209329921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 212222.

The product of its (nonzero) digits is 17496, while the sum is 37.

The square root of 209329921 is about 14468.2383516446. The cubic root of 209329921 is about 593.7593157393.

The spelling of 209329921 in words is "two hundred nine million, three hundred twenty-nine thousand, nine hundred twenty-one".