206561538 has 24 divisors (see below), whose sum is σ = 448297200. Its totient is φ = 68738904.

The previous prime is 206561513. The next prime is 206561561. The reversal of 206561538 is 835165602.

206561538 is a `hidden beast` number, since 2 + 0 + 6 + 5 + 615 + 38 = 666.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1873 + ... + 20411.

It is an arithmetic number, because the mean of its divisors is an integer number (18679050).

Almost surely, 2^206561538 is an apocalyptic number.

206561538 is an abundant number, since it is smaller than the sum of its proper divisors (241735662).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

206561538 is a wasteful number, since it uses less digits than its factorization.

206561538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19166 (or 19163 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The square root of 206561538 is about 14372.2488845692. The cubic root of 206561538 is about 591.1302074246.

The spelling of 206561538 in words is "two hundred six million, five hundred sixty-one thousand, five hundred thirty-eight".