231561205 has 4 divisors (see below), whose sum is σ = 277873452. Its totient is φ = 185248960.

The previous prime is 231561203. The next prime is 231561221. The reversal of 231561205 is 502165132.

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

It can be written as a sum of positive squares in 2 ways, for example, as 158407396 + 73153809 = 12586^2 + 8553^2 .

It is not a de Polignac number, because 231561205 - 2¹ = 231561203 is a prime.

It is a super-2 number, since 2×231561205² = 107241183322104050, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 231561205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231561203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23156116 + ... + 23156125.

It is an arithmetic number, because the mean of its divisors is an integer number (69468363).

Almost surely, 2^231561205 is an apocalyptic number.

It is an amenable number.

231561205 is a deficient number, since it is larger than the sum of its proper divisors (46312247).

231561205 is an equidigital number, since it uses as much as digits as its factorization.

231561205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46312246.

The product of its (nonzero) digits is 1800, while the sum is 25.

The square root of 231561205 is about 15217.1352428767. The cubic root of 231561205 is about 614.0757306315.

The spelling of 231561205 in words is "two hundred thirty-one million, five hundred sixty-one thousand, two hundred five".