206139 has 4 divisors (see below), whose sum is σ = 274856. Its totient is φ = 137424.

The previous prime is 206123. The next prime is 206153. The reversal of 206139 is 931602.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 206139 - 2⁴ = 206123 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (206179) 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, 34354 + ... + 34359.

It is an arithmetic number, because the mean of its divisors is an integer number (68714).

2²⁰⁶¹³⁹ is an apocalyptic number.

206139 is a deficient number, since it is larger than the sum of its proper divisors (68717).

206139 is an equidigital number, since it uses as much as digits as its factorization.

206139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68716.

The product of its (nonzero) digits is 324, while the sum is 21.

The square root of 206139 is about 454.0253296899. The cubic root of 206139 is about 59.0726864377.

The spelling of 206139 in words is "two hundred six thousand, one hundred thirty-nine".