213440209 has 2 divisors, whose sum is σ = 213440210. Its totient is φ = 213440208.

The previous prime is 213440179. The next prime is 213440231. The reversal of 213440209 is 902044312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 173712400 + 39727809 = 13180^2 + 6303^2 .

It is a cyclic number.

It is not a de Polignac number, because 213440209 - 2⁷ = 213440081 is a prime.

It is not a weakly prime, because it can be changed into another prime (213440009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106720104 + 106720105.

It is an arithmetic number, because the mean of its divisors is an integer number (106720105).

Almost surely, 2^213440209 is an apocalyptic number.

It is an amenable number.

213440209 is a deficient number, since it is larger than the sum of its proper divisors (1).

213440209 is an equidigital number, since it uses as much as digits as its factorization.

213440209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 213440209 is about 14609.5930470359. The cubic root of 213440209 is about 597.6203981160.

The spelling of 213440209 in words is "two hundred thirteen million, four hundred forty thousand, two hundred nine".