208821816 has 48 divisors (see below), whose sum is σ = 646354800. Its totient is φ = 59663232.

The previous prime is 208821791. The next prime is 208821817. The reversal of 208821816 is 618128802.

208821816 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (208821817) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 206661 + ... + 207668.

It is an arithmetic number, because the mean of its divisors is an integer number (13465725).

Almost surely, 2^208821816 is an apocalyptic number.

It is an amenable number.

208821816 is an abundant number, since it is smaller than the sum of its proper divisors (437532984).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

208821816 is a wasteful number, since it uses less digits than its factorization.

208821816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 414348 (or 414341 counting only the distinct ones).

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

The square root of 208821816 is about 14450.6683582456. The cubic root of 208821816 is about 593.2785172886.

The spelling of 208821816 in words is "two hundred eight million, eight hundred twenty-one thousand, eight hundred sixteen".