205431 has 4 divisors (see below), whose sum is σ = 273912. Its totient is φ = 136952.

The previous prime is 205427. The next prime is 205433. The reversal of 205431 is 134502.

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 205431 - 2² = 205427 is a prime.

It is a super-2 number, since 2×205431² = 84403791522, which contains 22 as substring.

It is an Ulam number.

It is a D-number.

It is a self number, because there is not a number n which added to its sum of digits gives 205431.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205433) 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, 34236 + ... + 34241.

It is an arithmetic number, because the mean of its divisors is an integer number (68478).

2²⁰⁵⁴³¹ is an apocalyptic number.

205431 is a deficient number, since it is larger than the sum of its proper divisors (68481).

205431 is an equidigital number, since it uses as much as digits as its factorization.

205431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68480.

The product of its (nonzero) digits is 120, while the sum is 15.

The square root of 205431 is about 453.2449668777. The cubic root of 205431 is about 59.0049789919.

Adding to 205431 its reverse (134502), we get a palindrome (339933).

It can be divided in two parts, 205 and 431, that added together give a palindrome (636).

The spelling of 205431 in words is "two hundred five thousand, four hundred thirty-one".