664749 has 12 divisors (see below), whose sum is σ = 967356. Its totient is φ = 439872.

The previous prime is 664739. The next prime is 664757. The reversal of 664749 is 947466.

664749 is a `hidden beast` number, since 6 + 647 + 4 + 9 = 666.

664749 is digitally balanced in base 7, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 79524 + 585225 = 282^2 + 765^2 .

It is not a de Polignac number, because 664749 - 2⁷ = 664621 is a prime.

664749 is strictly pandigital in base 7.

It is a Curzon number.

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 polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1939 + ... + 2255.

It is an arithmetic number, because the mean of its divisors is an integer number (80613).

2⁶⁶⁴⁷⁴⁹ is an apocalyptic number.

It is an amenable number.

664749 is a deficient number, since it is larger than the sum of its proper divisors (302607).

664749 is a wasteful number, since it uses less digits than its factorization.

664749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 556 (or 553 counting only the distinct ones).

The product of its digits is 36288, while the sum is 36.

The square root of 664749 is about 815.3214090161. The cubic root of 664749 is about 87.2742042245.

The spelling of 664749 in words is "six hundred sixty-four thousand, seven hundred forty-nine".