809281664 has 16 divisors (see below), whose sum is σ = 1612241070. Its totient is φ = 404640768.

The previous prime is 809281639. The next prime is 809281679. The reversal of 809281664 is 466182908.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 613057600 + 196224064 = 24760^2 + 14008^2 .

It is a tau number, because it is divible by the number of its divisors (16).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3161129 + ... + 3161384.

Almost surely, 2^809281664 is an apocalyptic number.

It is an amenable number.

809281664 is a deficient number, since it is larger than the sum of its proper divisors (802959406).

809281664 is an equidigital number, since it uses as much as digits as its factorization.

809281664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6322527 (or 6322515 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 44.

The square root of 809281664 is about 28447.8762651977. The cubic root of 809281664 is about 931.8941101676.

The spelling of 809281664 in words is "eight hundred nine million, two hundred eighty-one thousand, six hundred sixty-four".