664878 has 8 divisors (see below), whose sum is σ = 1329768. Its totient is φ = 221624.

The previous prime is 664849. The next prime is 664879. The reversal of 664878 is 878466.

It is a sphenic number, since it is the product of 3 distinct primes.

664878 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664879) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55401 + ... + 55412.

It is an arithmetic number, because the mean of its divisors is an integer number (166221).

2⁶⁶⁴⁸⁷⁸ is an apocalyptic number.

664878 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

664878 is a wasteful number, since it uses less digits than its factorization.

664878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110818.

The product of its digits is 64512, while the sum is 39.

The square root of 664878 is about 815.4005150845. The cubic root of 664878 is about 87.2798492846.

The spelling of 664878 in words is "six hundred sixty-four thousand, eight hundred seventy-eight".