206643621 has 8 divisors (see below), whose sum is σ = 276162880. Its totient is φ = 137443392.

The previous prime is 206643607. The next prime is 206643623. The reversal of 206643621 is 126346602.

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

It is not a de Polignac number, because 206643621 - 2¹⁴ = 206627237 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (206643623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 78241 + ... + 80838.

It is an arithmetic number, because the mean of its divisors is an integer number (34520360).

Almost surely, 2^206643621 is an apocalyptic number.

It is an amenable number.

206643621 is a deficient number, since it is larger than the sum of its proper divisors (69519259).

206643621 is a wasteful number, since it uses less digits than its factorization.

206643621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159515.

The product of its (nonzero) digits is 10368, while the sum is 30.

The square root of 206643621 is about 14375.1042083179. The cubic root of 206643621 is about 591.2084977581.

The spelling of 206643621 in words is "two hundred six million, six hundred forty-three thousand, six hundred twenty-one".