205561431 has 24 divisors (see below), whose sum is σ = 301523040. Its totient is φ = 134931456.

The previous prime is 205561429. The next prime is 205561451. The reversal of 205561431 is 134165502.

It is not a de Polignac number, because 205561431 - 2¹ = 205561429 is a prime.

It is a super-2 number, since 2×205561431² = 84511003829535522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 205561395 and 205561404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205561451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 282390 + ... + 283116.

It is an arithmetic number, because the mean of its divisors is an integer number (12563460).

Almost surely, 2^205561431 is an apocalyptic number.

205561431 is a deficient number, since it is larger than the sum of its proper divisors (95961609).

205561431 is a wasteful number, since it uses less digits than its factorization.

205561431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1175 (or 1172 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 205561431 is about 14337.4136789032. The cubic root of 205561431 is about 590.1746404395.

The spelling of 205561431 in words is "two hundred five million, five hundred sixty-one thousand, four hundred thirty-one".