209308091 has 2 divisors, whose sum is σ = 209308092. Its totient is φ = 209308090.

The previous prime is 209308069. The next prime is 209308139. The reversal of 209308091 is 190803902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 209308091 - 2¹⁰ = 209307067 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (209308591) 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, 104654045 + 104654046.

It is an arithmetic number, because the mean of its divisors is an integer number (104654046).

Almost surely, 2^209308091 is an apocalyptic number.

209308091 is a deficient number, since it is larger than the sum of its proper divisors (1).

209308091 is an equidigital number, since it uses as much as digits as its factorization.

209308091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888, while the sum is 32.

The square root of 209308091 is about 14467.4839208482. The cubic root of 209308091 is about 593.7386749308.

The spelling of 209308091 in words is "two hundred nine million, three hundred eight thousand, ninety-one".