1909309 has 2 divisors, whose sum is σ = 1909310. Its totient is φ = 1909308.

The previous prime is 1909307. The next prime is 1909319. The reversal of 1909309 is 9039091.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1493284 + 416025 = 1222^2 + 645^2 .

It is an emirp because it is prime and its reverse (9039091) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1909309 - 2¹ = 1909307 is a prime.

Together with 1909307, it forms a pair of twin primes.

1909309 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1909307) 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, 954654 + 954655.

It is an arithmetic number, because the mean of its divisors is an integer number (954655).

2^1909309 is an apocalyptic number.

It is an amenable number.

1909309 is a deficient number, since it is larger than the sum of its proper divisors (1).

1909309 is an equidigital number, since it uses as much as digits as its factorization.

1909309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2187, while the sum is 31.

The square root of 1909309 is about 1381.7774784675. Note that the first 3 decimals coincide. The cubic root of 1909309 is about 124.0581802940.

The spelling of 1909309 in words is "one million, nine hundred nine thousand, three hundred nine".