646566 has 8 divisors (see below), whose sum is σ = 1293144. Its totient is φ = 215520.

The previous prime is 646549. The next prime is 646571. The reversal of 646566 is 665646.

It is a sphenic number, since it is the product of 3 distinct primes.

646566 is an admirable number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53875 + ... + 53886.

It is an arithmetic number, because the mean of its divisors is an integer number (161643).

2⁶⁴⁶⁵⁶⁶ is an apocalyptic number.

646566 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

646566 is a wasteful number, since it uses less digits than its factorization.

646566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107766.

The product of its digits is 25920, while the sum is 33.

The square root of 646566 is about 804.0932781711. The cubic root of 646566 is about 86.4710941762.

The spelling of 646566 in words is "six hundred forty-six thousand, five hundred sixty-six".