213397909 has 2 divisors, whose sum is σ = 213397910. Its totient is φ = 213397908.

The previous prime is 213397903. The next prime is 213397931. The reversal of 213397909 is 909793312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 212722225 + 675684 = 14585^2 + 822^2 .

It is a cyclic number.

It is not a de Polignac number, because 213397909 - 2⁷ = 213397781 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213397903) 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, 106698954 + 106698955.

It is an arithmetic number, because the mean of its divisors is an integer number (106698955).

Almost surely, 2^213397909 is an apocalyptic number.

It is an amenable number.

213397909 is a deficient number, since it is larger than the sum of its proper divisors (1).

213397909 is an equidigital number, since it uses as much as digits as its factorization.

213397909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 91854, while the sum is 43.

The square root of 213397909 is about 14608.1452963749. The cubic root of 213397909 is about 597.5809163128.

The spelling of 213397909 in words is "two hundred thirteen million, three hundred ninety-seven thousand, nine hundred nine".