206561399 has 6 divisors (see below), whose sum is σ = 227046960. Its totient is φ = 187782980.

The previous prime is 206561389. The next prime is 206561423. The reversal of 206561399 is 993165602.

It is not a de Polignac number, because 206561399 - 2⁸ = 206561143 is a prime.

It is a super-2 number, since 2×206561399² = 85335223113674402, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (206561359) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 853439 + ... + 853680.

It is an arithmetic number, because the mean of its divisors is an integer number (37841160).

Almost surely, 2^206561399 is an apocalyptic number.

206561399 is a deficient number, since it is larger than the sum of its proper divisors (20485561).

206561399 is a wasteful number, since it uses less digits than its factorization.

206561399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1707141 (or 1707130 counting only the distinct ones).

The product of its (nonzero) digits is 87480, while the sum is 41.

The square root of 206561399 is about 14372.2440488603. The cubic root of 206561399 is about 591.1300748295.

The spelling of 206561399 in words is "two hundred six million, five hundred sixty-one thousand, three hundred ninety-nine".