206859409 has 2 divisors, whose sum is σ = 206859410. Its totient is φ = 206859408.

The previous prime is 206859397. The next prime is 206859421. The reversal of 206859409 is 904958602.

It is a balanced prime because it is at equal distance from previous prime (206859397) and next prime (206859421).

It can be written as a sum of positive squares in only one way, i.e., 169000000 + 37859409 = 13000^2 + 6153^2 .

It is a cyclic number.

It is not a de Polignac number, because 206859409 - 2⁵ = 206859377 is a prime.

It is not a weakly prime, because it can be changed into another prime (206859469) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103429704 + 103429705.

It is an arithmetic number, because the mean of its divisors is an integer number (103429705).

Almost surely, 2^206859409 is an apocalyptic number.

It is an amenable number.

206859409 is a deficient number, since it is larger than the sum of its proper divisors (1).

206859409 is an equidigital number, since it uses as much as digits as its factorization.

206859409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 155520, while the sum is 43.

The square root of 206859409 is about 14382.6078650570. The cubic root of 206859409 is about 591.4142163722.

The spelling of 206859409 in words is "two hundred six million, eight hundred fifty-nine thousand, four hundred nine".