646818 has 16 divisors (see below), whose sum is σ = 1313760. Its totient is φ = 212256.

The previous prime is 646781. The next prime is 646823. The reversal of 646818 is 818646.

It is an unprimeable number.

646818 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, 403 + ... + 1206.

It is an arithmetic number, because the mean of its divisors is an integer number (82110).

2⁶⁴⁶⁸¹⁸ is an apocalyptic number.

646818 is an abundant number, since it is smaller than the sum of its proper divisors (666942).

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

646818 is a wasteful number, since it uses less digits than its factorization.

646818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1681.

The product of its digits is 9216, while the sum is 33.

The square root of 646818 is about 804.2499611439. The cubic root of 646818 is about 86.4823267935.

The spelling of 646818 in words is "six hundred forty-six thousand, eight hundred eighteen".