206443861 has 4 divisors (see below), whose sum is σ = 222324172. Its totient is φ = 190563552.

The previous prime is 206443859. The next prime is 206443879. The reversal of 206443861 is 168344602.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18232900 + 188210961 = 4270^2 + 13719^2 .

It is a cyclic number.

It is not a de Polignac number, because 206443861 - 2¹ = 206443859 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (206443261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7940136 + ... + 7940161.

It is an arithmetic number, because the mean of its divisors is an integer number (55581043).

Almost surely, 2^206443861 is an apocalyptic number.

It is an amenable number.

206443861 is a deficient number, since it is larger than the sum of its proper divisors (15880311).

206443861 is a wasteful number, since it uses less digits than its factorization.

206443861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15880310.

The product of its (nonzero) digits is 27648, while the sum is 34.

The square root of 206443861 is about 14368.1544047940. The cubic root of 206443861 is about 591.0179315316.

The spelling of 206443861 in words is "two hundred six million, four hundred forty-three thousand, eight hundred sixty-one".