206418921 has 4 divisors (see below), whose sum is σ = 275225232. Its totient is φ = 137612612.

The previous prime is 206418917. The next prime is 206418931. The reversal of 206418921 is 129814602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 206418921 - 2² = 206418917 is a prime.

It is not an unprimeable number, because it can be changed into a prime (206418911) 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, 34403151 + ... + 34403156.

It is an arithmetic number, because the mean of its divisors is an integer number (68806308).

Almost surely, 2^206418921 is an apocalyptic number.

It is an amenable number.

206418921 is a deficient number, since it is larger than the sum of its proper divisors (68806311).

206418921 is an equidigital number, since it uses as much as digits as its factorization.

206418921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68806310.

The product of its (nonzero) digits is 6912, while the sum is 33.

The square root of 206418921 is about 14367.2864870163. The cubic root of 206418921 is about 590.9941307418.

The spelling of 206418921 in words is "two hundred six million, four hundred eighteen thousand, nine hundred twenty-one".