206412635561 has 24 divisors (see below), whose sum is σ = 229231503360. Its totient is φ = 184311036000.

The previous prime is 206412635551. The next prime is 206412635599. The reversal of 206412635561 is 165536214602.

It is a happy number.

206412635561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a de Polignac number, because none of the positive numbers 2^k-206412635561 is a prime.

It is a super-2 number, since 2×206412635561² (a number of 23 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (41) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (206412635521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17913560 + ... + 17925078.

It is an arithmetic number, because the mean of its divisors is an integer number (9551312640).

Almost surely, 2^206412635561 is an apocalyptic number.

It is an amenable number.

206412635561 is a deficient number, since it is larger than the sum of its proper divisors (22818867799).

206412635561 is a wasteful number, since it uses less digits than its factorization.

206412635561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11885 (or 11758 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 41.

The spelling of 206412635561 in words is "two hundred six billion, four hundred twelve million, six hundred thirty-five thousand, five hundred sixty-one".