205687864631 has 2 divisors, whose sum is σ = 205687864632. Its totient is φ = 205687864630.

The previous prime is 205687864621. The next prime is 205687864661. The reversal of 205687864631 is 136468786502.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 205687864631 - 2¹⁰ = 205687863607 is a prime.

It is a super-2 number, since 2×205687864631² (a number of 23 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205687864621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102843932315 + 102843932316.

It is an arithmetic number, because the mean of its divisors is an integer number (102843932316).

Almost surely, 2^205687864631 is an apocalyptic number.

205687864631 is a deficient number, since it is larger than the sum of its proper divisors (1).

205687864631 is an equidigital number, since it uses as much as digits as its factorization.

205687864631 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11612160, while the sum is 56.

The spelling of 205687864631 in words is "two hundred five billion, six hundred eighty-seven million, eight hundred sixty-four thousand, six hundred thirty-one".