205656641 has 2 divisors, whose sum is σ = 205656642. Its totient is φ = 205656640.

The previous prime is 205656637. The next prime is 205656643. The reversal of 205656641 is 146656502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 205320241 + 336400 = 14329^2 + 580^2 .

It is a cyclic number.

It is not a de Polignac number, because 205656641 - 2² = 205656637 is a prime.

Together with 205656643, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (205656643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102828320 + 102828321.

It is an arithmetic number, because the mean of its divisors is an integer number (102828321).

Almost surely, 2^205656641 is an apocalyptic number.

It is an amenable number.

205656641 is a deficient number, since it is larger than the sum of its proper divisors (1).

205656641 is an equidigital number, since it uses as much as digits as its factorization.

205656641 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 43200, while the sum is 35.

The square root of 205656641 is about 14340.7336283748. The cubic root of 205656641 is about 590.2657435454.

The spelling of 205656641 in words is "two hundred five million, six hundred fifty-six thousand, six hundred forty-one".