208665641 has 2 divisors, whose sum is σ = 208665642. Its totient is φ = 208665640.

The previous prime is 208665559. The next prime is 208665647. The reversal of 208665641 is 146566802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 207216025 + 1449616 = 14395^2 + 1204^2 .

It is a cyclic number.

It is not a de Polignac number, because 208665641 - 2¹⁸ = 208403497 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 208665595 and 208665604.

It is not a weakly prime, because it can be changed into another prime (208665647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104332820 + 104332821.

It is an arithmetic number, because the mean of its divisors is an integer number (104332821).

Almost surely, 2^208665641 is an apocalyptic number.

It is an amenable number.

208665641 is a deficient number, since it is larger than the sum of its proper divisors (1).

208665641 is an equidigital number, since it uses as much as digits as its factorization.

208665641 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 69120, while the sum is 38.

The square root of 208665641 is about 14445.2636182245. The cubic root of 208665641 is about 593.1305787536.

The spelling of 208665641 in words is "two hundred eight million, six hundred sixty-five thousand, six hundred forty-one".