208668561 has 8 divisors (see below), whose sum is σ = 280067904. Its totient is φ = 138190800.

The previous prime is 208668539. The next prime is 208668563. The reversal of 208668561 is 165866802.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 208668561 - 2⁶ = 208668497 is a prime.

It is not an unprimeable number, because it can be changed into a prime (208668563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 229866 + ... + 230771.

It is an arithmetic number, because the mean of its divisors is an integer number (35008488).

Almost surely, 2^208668561 is an apocalyptic number.

It is an amenable number.

208668561 is a deficient number, since it is larger than the sum of its proper divisors (71399343).

208668561 is a wasteful number, since it uses less digits than its factorization.

208668561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 460791.

The product of its (nonzero) digits is 138240, while the sum is 42.

The square root of 208668561 is about 14445.3646890620. The cubic root of 208668561 is about 593.1333454337.

The spelling of 208668561 in words is "two hundred eight million, six hundred sixty-eight thousand, five hundred sixty-one".