209938439 has 2 divisors, whose sum is σ = 209938440. Its totient is φ = 209938438.

The previous prime is 209938367. The next prime is 209938489. The reversal of 209938439 is 934839902.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 209938439 - 2²⁴ = 193161223 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 209938393 and 209938402.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (209938489) 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, 104969219 + 104969220.

It is an arithmetic number, because the mean of its divisors is an integer number (104969220).

Almost surely, 2^209938439 is an apocalyptic number.

209938439 is a deficient number, since it is larger than the sum of its proper divisors (1).

209938439 is an equidigital number, since it uses as much as digits as its factorization.

209938439 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 419904, while the sum is 47.

The square root of 209938439 is about 14489.2525342062. The cubic root of 209938439 is about 594.3341080476.

The spelling of 209938439 in words is "two hundred nine million, nine hundred thirty-eight thousand, four hundred thirty-nine".