206643728 has 20 divisors (see below), whose sum is σ = 405859068. Its totient is φ = 101905920.

The previous prime is 206643727. The next prime is 206643751. The reversal of 206643728 is 827346602.

It can be written as a sum of positive squares in 2 ways, for example, as 110838784 + 95804944 = 10528^2 + 9788^2 .

It is a hoax number, since the sum of its digits (38) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 206643691 and 206643700.

It is not an unprimeable number, because it can be changed into a prime (206643727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 87293 + ... + 89628.

Almost surely, 2^206643728 is an apocalyptic number.

It is an amenable number.

206643728 is a deficient number, since it is larger than the sum of its proper divisors (199215340).

206643728 is a wasteful number, since it uses less digits than its factorization.

206643728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 177002 (or 176996 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 38.

The square root of 206643728 is about 14375.1079300296. The cubic root of 206643728 is about 591.2085998006.

The spelling of 206643728 in words is "two hundred six million, six hundred forty-three thousand, seven hundred twenty-eight".