206640617 has 2 divisors, whose sum is σ = 206640618. Its totient is φ = 206640616.

The previous prime is 206640607. The next prime is 206640667. The reversal of 206640617 is 716046602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 133726096 + 72914521 = 11564^2 + 8539^2 .

It is a cyclic number.

It is not a de Polignac number, because 206640617 - 2¹⁰ = 206639593 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (206640607) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103320308 + 103320309.

It is an arithmetic number, because the mean of its divisors is an integer number (103320309).

Almost surely, 2^206640617 is an apocalyptic number.

It is an amenable number.

206640617 is a deficient number, since it is larger than the sum of its proper divisors (1).

206640617 is an equidigital number, since it uses as much as digits as its factorization.

206640617 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12096, while the sum is 32.

The square root of 206640617 is about 14374.9997217391. Note that the first 3 decimals coincide. The cubic root of 206640617 is about 591.2056329242.

The spelling of 206640617 in words is "two hundred six million, six hundred forty thousand, six hundred seventeen".