206916561 has 12 divisors (see below), whose sum is σ = 299004160. Its totient is φ = 137886840.

The previous prime is 206916557. The next prime is 206916581. The reversal of 206916561 is 165619602.

206916561 is a `hidden beast` number, since 2 + 0 + 6 + 91 + 6 + 561 = 666.

206916561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 206916561 - 2² = 206916557 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (206916511) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 40416 + ... + 45246.

Almost surely, 2^206916561 is an apocalyptic number.

It is an amenable number.

206916561 is a deficient number, since it is larger than the sum of its proper divisors (92087599).

206916561 is a wasteful number, since it uses less digits than its factorization.

206916561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9596 (or 9593 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

The square root of 206916561 is about 14384.5945719718. The cubic root of 206916561 is about 591.4686775045.

The spelling of 206916561 in words is "two hundred six million, nine hundred sixteen thousand, five hundred sixty-one".