208668643 has 2 divisors, whose sum is σ = 208668644. Its totient is φ = 208668642.

The previous prime is 208668623. The next prime is 208668653. The reversal of 208668643 is 346866802.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 208668643 - 2⁵ = 208668611 is a prime.

It is a super-2 number, since 2×208668643² = 87085205142922898, which contains 22 as substring.

It is a zygodrome in base 2.

It is a self number, because there is not a number n which added to its sum of digits gives 208668643.

It is not a weakly prime, because it can be changed into another prime (208668623) 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, 104334321 + 104334322.

It is an arithmetic number, because the mean of its divisors is an integer number (104334322).

Almost surely, 2^208668643 is an apocalyptic number.

208668643 is a deficient number, since it is larger than the sum of its proper divisors (1).

208668643 is an equidigital number, since it uses as much as digits as its factorization.

208668643 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 331776, while the sum is 43.

The square root of 208668643 is about 14445.3675273425. The cubic root of 208668643 is about 593.1334231277.

The spelling of 208668643 in words is "two hundred eight million, six hundred sixty-eight thousand, six hundred forty-three".