646684 has 24 divisors (see below), whose sum is σ = 1218560. Its totient is φ = 299376.

The previous prime is 646669. The next prime is 646687. The reversal of 646684 is 486646.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646687) by changing a digit.

646684 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 in 7 ways as a sum of consecutive naturals, for example, 5029 + ... + 5155.

2⁶⁴⁶⁶⁸⁴ is an apocalyptic number.

It is an amenable number.

646684 is a deficient number, since it is larger than the sum of its proper divisors (571876).

646684 is a wasteful number, since it uses less digits than its factorization.

646684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 217 (or 215 counting only the distinct ones).

The product of its digits is 27648, while the sum is 34.

The square root of 646684 is about 804.1666493955. The cubic root of 646684 is about 86.4763542571.

The spelling of 646684 in words is "six hundred forty-six thousand, six hundred eighty-four".