664864985 has 8 divisors (see below), whose sum is σ = 844769736. Its totient is φ = 500604160.

The previous prime is 664864931. The next prime is 664864987. The reversal of 664864985 is 589468466.

It can be written as a sum of positive squares in 4 ways, for example, as 89056969 + 575808016 = 9437^2 + 23996^2 .

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

It is not a de Polignac number, because 664864985 - 2¹⁰ = 664863961 is a prime.

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 664864985.

It is not an unprimeable number, because it can be changed into a prime (664864987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3910886 + ... + 3911055.

It is an arithmetic number, because the mean of its divisors is an integer number (105596217).

Almost surely, 2^664864985 is an apocalyptic number.

It is an amenable number.

664864985 is a deficient number, since it is larger than the sum of its proper divisors (179904751).

664864985 is a wasteful number, since it uses less digits than its factorization.

664864985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7821963.

The product of its digits is 9953280, while the sum is 56.

The square root of 664864985 is about 25784.9759550014. The cubic root of 664864985 is about 872.7927977932.

The spelling of 664864985 in words is "six hundred sixty-four million, eight hundred sixty-four thousand, nine hundred eighty-five".