206646999557 has 2 divisors, whose sum is σ = 206646999558. Its totient is φ = 206646999556.

The previous prime is 206646999529. The next prime is 206646999589. The reversal of 206646999557 is 755999646602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 206434831201 + 212168356 = 454351^2 + 14566^2 .

It is a cyclic number.

It is not a de Polignac number, because 206646999557 - 2³⁰ = 205573257733 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (206646999527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103323499778 + 103323499779.

It is an arithmetic number, because the mean of its divisors is an integer number (103323499779).

Almost surely, 2^206646999557 is an apocalyptic number.

It is an amenable number.

206646999557 is a deficient number, since it is larger than the sum of its proper divisors (1).

206646999557 is an equidigital number, since it uses as much as digits as its factorization.

206646999557 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 220449600, while the sum is 68.

The spelling of 206646999557 in words is "two hundred six billion, six hundred forty-six million, nine hundred ninety-nine thousand, five hundred fifty-seven".