646564 has 6 divisors (see below), whose sum is σ = 1131494. Its totient is φ = 323280.

The previous prime is 646549. The next prime is 646571. The reversal of 646564 is 465646.

It can be written as a sum of positive squares in only one way, i.e., 518400 + 128164 = 720^2 + 358^2 .

It is an unprimeable number.

646564 is an untouchable number, because it is not equal to the sum of proper divisors of any 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 as a sum of consecutive naturals, namely, 80817 + ... + 80824.

2⁶⁴⁶⁵⁶⁴ is an apocalyptic number.

It is an amenable number.

646564 is a deficient number, since it is larger than the sum of its proper divisors (484930).

646564 is a wasteful number, since it uses less digits than its factorization.

646564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161645 (or 161643 counting only the distinct ones).

The product of its digits is 17280, while the sum is 31.

The square root of 646564 is about 804.0920345334. The cubic root of 646564 is about 86.4710050168.

The spelling of 646564 in words is "six hundred forty-six thousand, five hundred sixty-four".