646804 has 12 divisors (see below), whose sum is σ = 1143828. Its totient is φ = 320000.

The previous prime is 646781. The next prime is 646823. The reversal of 646804 is 408646.

It can be written as a sum of positive squares in 2 ways, for example, as 636804 + 10000 = 798^2 + 100^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 397 + ... + 1204.

It is an arithmetic number, because the mean of its divisors is an integer number (95319).

2⁶⁴⁶⁸⁰⁴ is an apocalyptic number.

It is an amenable number.

646804 is a deficient number, since it is larger than the sum of its proper divisors (497024).

646804 is a wasteful number, since it uses less digits than its factorization.

646804 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1706 (or 1704 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 646804 is about 804.2412573351. The cubic root of 646804 is about 86.4817028358.

The spelling of 646804 in words is "six hundred forty-six thousand, eight hundred four".