819664 has 10 divisors (see below), whose sum is σ = 1588130. Its totient is φ = 409824.

The previous prime is 819659. The next prime is 819673. The reversal of 819664 is 466918.

It can be written as a sum of positive squares in only one way, i.e., 577600 + 242064 = 760^2 + 492^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25599 + ... + 25630.

It is an arithmetic number, because the mean of its divisors is an integer number (158813).

2⁸¹⁹⁶⁶⁴ is an apocalyptic number.

It is an amenable number.

819664 is a deficient number, since it is larger than the sum of its proper divisors (768466).

819664 is a wasteful number, since it uses less digits than its factorization.

819664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51237 (or 51231 counting only the distinct ones).

The product of its digits is 10368, while the sum is 34.

The square root of 819664 is about 905.3529698410. The cubic root of 819664 is about 93.5862302290.

The spelling of 819664 in words is "eight hundred nineteen thousand, six hundred sixty-four".