209144909 has 2 divisors, whose sum is σ = 209144910. Its totient is φ = 209144908.

The previous prime is 209144891. The next prime is 209144939. The reversal of 209144909 is 909441902.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 206726884 + 2418025 = 14378^2 + 1555^2 .

It is a cyclic number.

It is not a de Polignac number, because 209144909 - 2⁸ = 209144653 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (209144939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104572454 + 104572455.

It is an arithmetic number, because the mean of its divisors is an integer number (104572455).

Almost surely, 2^209144909 is an apocalyptic number.

It is an amenable number.

209144909 is a deficient number, since it is larger than the sum of its proper divisors (1).

209144909 is an equidigital number, since it uses as much as digits as its factorization.

209144909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 209144909 is about 14461.8432089412. The cubic root of 209144909 is about 593.5843368073.

The spelling of 209144909 in words is "two hundred nine million, one hundred forty-four thousand, nine hundred nine".