206662409 has 2 divisors, whose sum is σ = 206662410. Its totient is φ = 206662408.

The previous prime is 206662403. The next prime is 206662451. The reversal of 206662409 is 904266602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 201554809 + 5107600 = 14197^2 + 2260^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-206662409 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (206662403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103331204 + 103331205.

It is an arithmetic number, because the mean of its divisors is an integer number (103331205).

Almost surely, 2^206662409 is an apocalyptic number.

It is an amenable number.

206662409 is a deficient number, since it is larger than the sum of its proper divisors (1).

206662409 is an equidigital number, since it uses as much as digits as its factorization.

206662409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31104, while the sum is 35.

The square root of 206662409 is about 14375.7576843796. The cubic root of 206662409 is about 591.2264147377.

The spelling of 206662409 in words is "two hundred six million, six hundred sixty-two thousand, four hundred nine".