213023809 has 2 divisors, whose sum is σ = 213023810. Its totient is φ = 213023808.

The previous prime is 213023777. The next prime is 213023813. The reversal of 213023809 is 908320312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 212343184 + 680625 = 14572^2 + 825^2 .

It is a cyclic number.

It is not a de Polignac number, because 213023809 - 2⁵ = 213023777 is a prime.

It is not a weakly prime, because it can be changed into another prime (213023819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106511904 + 106511905.

It is an arithmetic number, because the mean of its divisors is an integer number (106511905).

Almost surely, 2^213023809 is an apocalyptic number.

It is an amenable number.

213023809 is a deficient number, since it is larger than the sum of its proper divisors (1).

213023809 is an equidigital number, since it uses as much as digits as its factorization.

213023809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 213023809 is about 14595.3351794332. The cubic root of 213023809 is about 597.2315130398.

The spelling of 213023809 in words is "two hundred thirteen million, twenty-three thousand, eight hundred nine".