209439634189 has 2 divisors, whose sum is σ = 209439634190. Its totient is φ = 209439634188.

The previous prime is 209439634169. The next prime is 209439634241. The reversal of 209439634189 is 981436934902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 105986058025 + 103453576164 = 325555^2 + 321642^2 .

It is a cyclic number.

It is not a de Polignac number, because 209439634189 - 2²¹ = 209437537037 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (209439634169) 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 as a sum of consecutive naturals, namely, 104719817094 + 104719817095.

It is an arithmetic number, because the mean of its divisors is an integer number (104719817095).

Almost surely, 2^209439634189 is an apocalyptic number.

It is an amenable number.

209439634189 is a deficient number, since it is larger than the sum of its proper divisors (1).

209439634189 is an equidigital number, since it uses as much as digits as its factorization.

209439634189 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10077696, while the sum is 58.

The spelling of 209439634189 in words is "two hundred nine billion, four hundred thirty-nine million, six hundred thirty-four thousand, one hundred eighty-nine".