664738 has 16 divisors (see below), whose sum is σ = 1052280. Its totient is φ = 314496.

The previous prime is 664711. The next prime is 664739. The reversal of 664738 is 837466.

664738 is nontrivially palindromic in base 8.

It can be written as a sum of positive squares in 4 ways, for example, as 537289 + 127449 = 733^2 + 357^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664739) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4156 + ... + 4312.

2⁶⁶⁴⁷³⁸ is an apocalyptic number.

664738 is a deficient number, since it is larger than the sum of its proper divisors (387542).

664738 is a wasteful number, since it uses less digits than its factorization.

664738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 261.

The product of its digits is 24192, while the sum is 34.

The square root of 664738 is about 815.3146631823. The cubic root of 664738 is about 87.2737228290.

The spelling of 664738 in words is "six hundred sixty-four thousand, seven hundred thirty-eight".