646518 has 16 divisors (see below), whose sum is σ = 1301040. Its totient is φ = 214176.

The previous prime is 646453. The next prime is 646519. The reversal of 646518 is 815646.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646519) by changing a digit.

646518 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 (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1468 + ... + 1856.

It is an arithmetic number, because the mean of its divisors is an integer number (81315).

2⁶⁴⁶⁵¹⁸ is an apocalyptic number.

646518 is an abundant number, since it is smaller than the sum of its proper divisors (654522).

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

646518 is a wasteful number, since it uses less digits than its factorization.

646518 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 671.

The product of its digits is 5760, while the sum is 30.

The square root of 646518 is about 804.0634303337. The cubic root of 646518 is about 86.4689542992.

The spelling of 646518 in words is "six hundred forty-six thousand, five hundred eighteen".