206510009 has 2 divisors, whose sum is σ = 206510010. Its totient is φ = 206510008.

The previous prime is 206509981. The next prime is 206510023. The reversal of 206510009 is 900015602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 183738025 + 22771984 = 13555^2 + 4772^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-206510009 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (206510039) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103255004 + 103255005.

It is an arithmetic number, because the mean of its divisors is an integer number (103255005).

Almost surely, 2^206510009 is an apocalyptic number.

It is an amenable number.

206510009 is a deficient number, since it is larger than the sum of its proper divisors (1).

206510009 is an equidigital number, since it uses as much as digits as its factorization.

206510009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 206510009 is about 14370.4561166304. The cubic root of 206510009 is about 591.0810487380.

The spelling of 206510009 in words is "two hundred six million, five hundred ten thousand, nine".