664678 has 16 divisors (see below), whose sum is σ = 1149984. Its totient is φ = 282240.

The previous prime is 664669. The next prime is 664679. The reversal of 664678 is 876466.

664678 is nontrivially palindromic in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664679) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2638 + ... + 2878.

It is an arithmetic number, because the mean of its divisors is an integer number (71874).

2⁶⁶⁴⁶⁷⁸ is an apocalyptic number.

664678 is a deficient number, since it is larger than the sum of its proper divisors (485306).

664678 is a wasteful number, since it uses less digits than its factorization.

664678 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 447.

The product of its digits is 48384, while the sum is 37.

The square root of 664678 is about 815.2778667424. The cubic root of 664678 is about 87.2710969419.

It can be divided in two parts, 6646 and 78, that added together give a square (6724 = 82²).

The spelling of 664678 in words is "six hundred sixty-four thousand, six hundred seventy-eight".