206838991 has 8 divisors (see below), whose sum is σ = 219755520. Its totient is φ = 194308128.

The previous prime is 206838979. The next prime is 206839001. The reversal of 206838991 is 199838602.

206838991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-206838991 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 (206838391) 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, 95311 + ... + 97456.

It is an arithmetic number, because the mean of its divisors is an integer number (27469440).

Almost surely, 2^206838991 is an apocalyptic number.

206838991 is a deficient number, since it is larger than the sum of its proper divisors (12916529).

206838991 is a wasteful number, since it uses less digits than its factorization.

206838991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192833.

The product of its (nonzero) digits is 186624, while the sum is 46.

The square root of 206838991 is about 14381.8980319011. The cubic root of 206838991 is about 591.3947572738.

The spelling of 206838991 in words is "two hundred six million, eight hundred thirty-eight thousand, nine hundred ninety-one".