205340123 has 4 divisors (see below), whose sum is σ = 205409280. Its totient is φ = 205270968.

The previous prime is 205340111. The next prime is 205340129. The reversal of 205340123 is 321043502.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 205340123 - 2⁸ = 205339867 is a prime.

It is a super-2 number, since 2×205340123² = 84329132227310258, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 205340095 and 205340104.

It is not an unprimeable number, because it can be changed into a prime (205340129) 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, 29915 + ... + 36132.

It is an arithmetic number, because the mean of its divisors is an integer number (51352320).

Almost surely, 2^205340123 is an apocalyptic number.

205340123 is a deficient number, since it is larger than the sum of its proper divisors (69157).

205340123 is an equidigital number, since it uses as much as digits as its factorization.

205340123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69156.

The product of its (nonzero) digits is 720, while the sum is 20.

The square root of 205340123 is about 14329.6937510890. The cubic root of 205340123 is about 589.9627698427.

Adding to 205340123 its reverse (321043502), we get a palindrome (526383625).

The spelling of 205340123 in words is "two hundred five million, three hundred forty thousand, one hundred twenty-three".