664818 has 32 divisors (see below), whose sum is σ = 1658880. Its totient is φ = 172560.

The previous prime is 664799. The next prime is 664843. The reversal of 664818 is 818466.

It is a Harshad number since it is a multiple of its sum of digits (33).

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 15 ways as a sum of consecutive naturals, for example, 258 + ... + 1181.

It is an arithmetic number, because the mean of its divisors is an integer number (51840).

2⁶⁶⁴⁸¹⁸ is an apocalyptic number.

664818 is an abundant number, since it is smaller than the sum of its proper divisors (994062).

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

664818 is a wasteful number, since it uses less digits than its factorization.

664818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1462.

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

The square root of 664818 is about 815.3637225190. The cubic root of 664818 is about 87.2772237661.

It can be divided in two parts, 6648 and 18, that added together give a palindrome (6666).

The spelling of 664818 in words is "six hundred sixty-four thousand, eight hundred eighteen".