208809664 has 56 divisors (see below), whose sum is σ = 478962720. Its totient is φ = 88467456.

The previous prime is 208809631. The next prime is 208809701. The reversal of 208809664 is 466908802.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (56).

It is a hoax number, since the sum of its digits (43) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 208809664.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37254 + ... + 42490.

Almost surely, 2^208809664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 208809664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (239481360).

208809664 is an abundant number, since it is smaller than the sum of its proper divisors (270153056).

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

208809664 is an equidigital number, since it uses as much as digits as its factorization.

208809664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5345 (or 5335 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 43.

The square root of 208809664 is about 14450.2478871471. The cubic root of 208809664 is about 593.2670088160.

The spelling of 208809664 in words is "two hundred eight million, eight hundred nine thousand, six hundred sixty-four".