664779685 has 8 divisors (see below), whose sum is σ = 799084440. Its totient is φ = 530924544.

The previous prime is 664779667. The next prime is 664779691. The reversal of 664779685 is 586977466.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 47306884 + 617472801 = 6878^2 + 24849^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 664779685 - 2⁵ = 664779653 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 109140 + ... + 115069.

It is an arithmetic number, because the mean of its divisors is an integer number (99885555).

Almost surely, 2^664779685 is an apocalyptic number.

It is an amenable number.

664779685 is a deficient number, since it is larger than the sum of its proper divisors (134304755).

664779685 is a wasteful number, since it uses less digits than its factorization.

664779685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 224807.

The product of its digits is 15240960, while the sum is 58.

The square root of 664779685 is about 25783.3218379634. The cubic root of 664779685 is about 872.7554707111.

The spelling of 664779685 in words is "six hundred sixty-four million, seven hundred seventy-nine thousand, six hundred eighty-five".