213816209 has 2 divisors, whose sum is σ = 213816210. Its totient is φ = 213816208.

The previous prime is 213816193. The next prime is 213816241. The reversal of 213816209 is 902618312.

It is an a-pointer prime, because the next prime (213816241) can be obtained adding 213816209 to its sum of digits (32).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 126337600 + 87478609 = 11240^2 + 9353^2 .

It is a cyclic number.

It is not a de Polignac number, because 213816209 - 2⁴ = 213816193 is a prime.

It is a super-2 number, since 2×213816209² = 91434742462263362, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (213816289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106908104 + 106908105.

It is an arithmetic number, because the mean of its divisors is an integer number (106908105).

Almost surely, 2^213816209 is an apocalyptic number.

It is an amenable number.

213816209 is a deficient number, since it is larger than the sum of its proper divisors (1).

213816209 is an equidigital number, since it uses as much as digits as its factorization.

213816209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 213816209 is about 14622.4556419228. The cubic root of 213816209 is about 597.9711184285.

The spelling of 213816209 in words is "two hundred thirteen million, eight hundred sixteen thousand, two hundred nine".