206731661 has 2 divisors, whose sum is σ = 206731662. Its totient is φ = 206731660.

The previous prime is 206731643. The next prime is 206731699. The reversal of 206731661 is 166137602.

206731661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 117050761 + 89680900 = 10819^2 + 9470^2 .

It is a cyclic number.

It is not a de Polignac number, because 206731661 - 2¹⁰ = 206730637 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (206731601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103365830 + 103365831.

It is an arithmetic number, because the mean of its divisors is an integer number (103365831).

Almost surely, 2^206731661 is an apocalyptic number.

It is an amenable number.

206731661 is a deficient number, since it is larger than the sum of its proper divisors (1).

206731661 is an equidigital number, since it uses as much as digits as its factorization.

206731661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9072, while the sum is 32.

The square root of 206731661 is about 14378.1661208932. The cubic root of 206731661 is about 591.2924468064.

The spelling of 206731661 in words is "two hundred six million, seven hundred thirty-one thousand, six hundred sixty-one".