664489909 has 4 divisors (see below), whose sum is σ = 664845804. Its totient is φ = 664134016.

The previous prime is 664489871. The next prime is 664489937. The reversal of 664489909 is 909984466.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 358344900 + 306145009 = 18930^2 + 17497^2 .

It is a cyclic number.

It is not a de Polignac number, because 664489909 - 2¹³ = 664481717 is a prime.

It is a super-4 number, since 4×664489909⁴ (a number of 36 digits) contains 4444 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 664489909.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664489939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 175132 + ... + 178885.

It is an arithmetic number, because the mean of its divisors is an integer number (166211451).

Almost surely, 2^664489909 is an apocalyptic number.

It is an amenable number.

664489909 is a deficient number, since it is larger than the sum of its proper divisors (355895).

664489909 is a wasteful number, since it uses less digits than its factorization.

664489909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 355894.

The product of its (nonzero) digits is 3359232, while the sum is 55.

The square root of 664489909 is about 25777.7017788631. The cubic root of 664489909 is about 872.6286415522.

The spelling of 664489909 in words is "six hundred sixty-four million, four hundred eighty-nine thousand, nine hundred nine".