206128213 has 4 divisors (see below), whose sum is σ = 218253420. Its totient is φ = 194003008.

The previous prime is 206128199. The next prime is 206128253. The reversal of 206128213 is 312821602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 312821602 = 2 ⋅156410801.

It can be written as a sum of positive squares in 2 ways, for example, as 98446084 + 107682129 = 9922^2 + 10377^2 .

It is a cyclic number.

It is not a de Polignac number, because 206128213 - 2²⁵ = 172573781 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 (206128253) 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 3 ways as a sum of consecutive naturals, for example, 6062578 + ... + 6062611.

It is an arithmetic number, because the mean of its divisors is an integer number (54563355).

Almost surely, 2^206128213 is an apocalyptic number.

It is an amenable number.

206128213 is a deficient number, since it is larger than the sum of its proper divisors (12125207).

206128213 is a wasteful number, since it uses less digits than its factorization.

206128213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12125206.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 206128213 is about 14357.1659111400. The cubic root of 206128213 is about 590.7165601939.

Adding to 206128213 its reverse (312821602), we get a palindrome (518949815).

The spelling of 206128213 in words is "two hundred six million, one hundred twenty-eight thousand, two hundred thirteen".