208685664 has 144 divisors (see below), whose sum is σ = 681670080. Its totient is φ = 59892480.

The previous prime is 208685657. The next prime is 208685671. The reversal of 208685664 is 466586802.

208685664 is a `hidden beast` number, since 2 + 0 + 86 + 8 + 566 + 4 = 666.

It is an interprime number because it is at equal distance from previous prime (208685657) and next prime (208685671).

It is a tau number, because it is divible by the number of its divisors (144).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 58459 + ... + 61925.

It is an arithmetic number, because the mean of its divisors is an integer number (4733820).

Almost surely, 2^208685664 is an apocalyptic number.

208685664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 208685664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (340835040).

208685664 is an abundant number, since it is smaller than the sum of its proper divisors (472984416).

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

208685664 is a wasteful number, since it uses less digits than its factorization.

208685664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3513 (or 3502 counting only the distinct ones).

The product of its (nonzero) digits is 552960, while the sum is 45.

The square root of 208685664 is about 14445.9566661402. The cubic root of 208685664 is about 593.1495498911.

The spelling of 208685664 in words is "two hundred eight million, six hundred eighty-five thousand, six hundred sixty-four".