209340409 has 4 divisors (see below), whose sum is σ = 209468404. Its totient is φ = 209212416.

The previous prime is 209340403. The next prime is 209340419. The reversal of 209340409 is 904043902.

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

It can be written as a sum of positive squares in 2 ways, for example, as 133911184 + 75429225 = 11572^2 + 8685^2 .

It is a cyclic number.

It is not a de Polignac number, because 209340409 - 2³ = 209340401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (209340401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61512 + ... + 64825.

It is an arithmetic number, because the mean of its divisors is an integer number (52367101).

Almost surely, 2^209340409 is an apocalyptic number.

It is an amenable number.

209340409 is a deficient number, since it is larger than the sum of its proper divisors (127995).

209340409 is a wasteful number, since it uses less digits than its factorization.

209340409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127994.

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 209340409 is about 14468.6007962069. The cubic root of 209340409 is about 593.7692318941.

The spelling of 209340409 in words is "two hundred nine million, three hundred forty thousand, four hundred nine".