664604661 has 8 divisors (see below), whose sum is σ = 1012730944. Its totient is φ = 379774080.

The previous prime is 664604657. The next prime is 664604671. The reversal of 664604661 is 166406466.

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

It is not a de Polignac number, because 664604661 - 2² = 664604657 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664604651) 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 7 ways as a sum of consecutive naturals, for example, 15823900 + ... + 15823941.

It is an arithmetic number, because the mean of its divisors is an integer number (126591368).

Almost surely, 2^664604661 is an apocalyptic number.

It is an amenable number.

664604661 is a deficient number, since it is larger than the sum of its proper divisors (348126283).

664604661 is a wasteful number, since it uses less digits than its factorization.

664604661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31647851.

The product of its (nonzero) digits is 124416, while the sum is 39.

The square root of 664604661 is about 25779.9274824426. The cubic root of 664604661 is about 872.6788706160.

The spelling of 664604661 in words is "six hundred sixty-four million, six hundred four thousand, six hundred sixty-one".