206856021 has 8 divisors (see below), whose sum is σ = 290324320. Its totient is φ = 130645872.

The previous prime is 206856007. The next prime is 206856061. The reversal of 206856021 is 120658602.

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

It is not a de Polignac number, because 206856021 - 2⁷ = 206855893 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 206856021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (206856061) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1814470 + ... + 1814583.

It is an arithmetic number, because the mean of its divisors is an integer number (36290540).

Almost surely, 2^206856021 is an apocalyptic number.

It is an amenable number.

206856021 is a deficient number, since it is larger than the sum of its proper divisors (83468299).

206856021 is a wasteful number, since it uses less digits than its factorization.

206856021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3629075.

The product of its (nonzero) digits is 5760, while the sum is 30.

The square root of 206856021 is about 14382.4900834313. The cubic root of 206856021 is about 591.4109875733.

The spelling of 206856021 in words is "two hundred six million, eight hundred fifty-six thousand, twenty-one".