205855831 has 2 divisors, whose sum is σ = 205855832. Its totient is φ = 205855830.

The previous prime is 205855813. The next prime is 205855913. The reversal of 205855831 is 138558502.

Together with previous prime (205855813) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 205855831 - 2¹¹ = 205853783 is a prime.

It is a super-2 number, since 2×205855831² = 84753246313401122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205855801) 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 as a sum of consecutive naturals, namely, 102927915 + 102927916.

It is an arithmetic number, because the mean of its divisors is an integer number (102927916).

Almost surely, 2^205855831 is an apocalyptic number.

205855831 is a deficient number, since it is larger than the sum of its proper divisors (1).

205855831 is an equidigital number, since it uses as much as digits as its factorization.

205855831 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48000, while the sum is 37.

The square root of 205855831 is about 14347.6768502779. The cubic root of 205855831 is about 590.4562505542.

The spelling of 205855831 in words is "two hundred five million, eight hundred fifty-five thousand, eight hundred thirty-one".