208681821 has 24 divisors (see below), whose sum is σ = 305338176. Its totient is φ = 137329920.

The previous prime is 208681799. The next prime is 208681831. The reversal of 208681821 is 128186802.

It is not a de Polignac number, because 208681821 - 2⁵ = 208681789 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (208681831) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 309741 + ... + 310413.

It is an arithmetic number, because the mean of its divisors is an integer number (12722424).

Almost surely, 2^208681821 is an apocalyptic number.

It is an amenable number.

208681821 is a deficient number, since it is larger than the sum of its proper divisors (96656355).

208681821 is a wasteful number, since it uses less digits than its factorization.

208681821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1073 (or 1070 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 36.

The square root of 208681821 is about 14445.8236525302. The cubic root of 208681821 is about 593.1459088685.

The spelling of 208681821 in words is "two hundred eight million, six hundred eighty-one thousand, eight hundred twenty-one".