205661983 has 2 divisors, whose sum is σ = 205661984. Its totient is φ = 205661982.

The previous prime is 205661917. The next prime is 205662013. The reversal of 205661983 is 389166502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 205661983 - 2²¹ = 203564831 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205661083) 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, 102830991 + 102830992.

It is an arithmetic number, because the mean of its divisors is an integer number (102830992).

Almost surely, 2^205661983 is an apocalyptic number.

205661983 is a deficient number, since it is larger than the sum of its proper divisors (1).

205661983 is an equidigital number, since it uses as much as digits as its factorization.

205661983 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 77760, while the sum is 40.

The square root of 205661983 is about 14340.9198798403. The cubic root of 205661983 is about 590.2708542845.

The spelling of 205661983 in words is "two hundred five million, six hundred sixty-one thousand, nine hundred eighty-three".