206643643 has 8 divisors (see below), whose sum is σ = 208878912. Its totient is φ = 204414216.

The previous prime is 206643641. The next prime is 206643683. The reversal of 206643643 is 346346602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 206643643 - 2¹ = 206643641 is a prime.

It is a super-2 number, since 2×206643643² = 85403190384622898, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 206643599 and 206643608.

It is not an unprimeable number, because it can be changed into a prime (206643641) 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 7 ways as a sum of consecutive naturals, for example, 126196 + ... + 127822.

It is an arithmetic number, because the mean of its divisors is an integer number (26109864).

Almost surely, 2^206643643 is an apocalyptic number.

206643643 is a deficient number, since it is larger than the sum of its proper divisors (2235269).

206643643 is a wasteful number, since it uses less digits than its factorization.

206643643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2921.

The product of its (nonzero) digits is 62208, while the sum is 34.

The square root of 206643643 is about 14375.1049735298. The cubic root of 206643643 is about 591.2085187388.

The spelling of 206643643 in words is "two hundred six million, six hundred forty-three thousand, six hundred forty-three".