206630509 has 2 divisors, whose sum is σ = 206630510. Its totient is φ = 206630508.

The previous prime is 206630507. The next prime is 206630549. The reversal of 206630509 is 905036602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 132756484 + 73874025 = 11522^2 + 8595^2 .

It is a cyclic number.

It is not a de Polignac number, because 206630509 - 2¹ = 206630507 is a prime.

Together with 206630507, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (206630503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103315254 + 103315255.

It is an arithmetic number, because the mean of its divisors is an integer number (103315255).

Almost surely, 2^206630509 is an apocalyptic number.

It is an amenable number.

206630509 is a deficient number, since it is larger than the sum of its proper divisors (1).

206630509 is an equidigital number, since it uses as much as digits as its factorization.

206630509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9720, while the sum is 31.

The square root of 206630509 is about 14374.6481348240. The cubic root of 206630509 is about 591.1959929930.

The spelling of 206630509 in words is "two hundred six million, six hundred thirty thousand, five hundred nine".