209120878909 has 2 divisors, whose sum is σ = 209120878910. Its totient is φ = 209120878908.

The previous prime is 209120878903. The next prime is 209120878951. The reversal of 209120878909 is 909878021902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 149741911225 + 59378967684 = 386965^2 + 243678^2 .

It is a cyclic number.

It is not a de Polignac number, because 209120878909 - 2⁷ = 209120878781 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 209120878909.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (209120878903) 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, 104560439454 + 104560439455.

It is an arithmetic number, because the mean of its divisors is an integer number (104560439455).

Almost surely, 2^209120878909 is an apocalyptic number.

It is an amenable number.

209120878909 is a deficient number, since it is larger than the sum of its proper divisors (1).

209120878909 is an equidigital number, since it uses as much as digits as its factorization.

209120878909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1306368, while the sum is 55.

The spelling of 209120878909 in words is "two hundred nine billion, one hundred twenty million, eight hundred seventy-eight thousand, nine hundred nine".