664445615 has 4 divisors (see below), whose sum is σ = 797334744. Its totient is φ = 531556488.

The previous prime is 664445603. The next prime is 664445623. The reversal of 664445615 is 516544466.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-664445615 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66444557 + ... + 66444566.

It is an arithmetic number, because the mean of its divisors is an integer number (199333686).

Almost surely, 2^664445615 is an apocalyptic number.

664445615 is a deficient number, since it is larger than the sum of its proper divisors (132889129).

664445615 is a wasteful number, since it uses less digits than its factorization.

664445615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132889128.

The product of its digits is 345600, while the sum is 41.

The square root of 664445615 is about 25776.8426111500. The cubic root of 664445615 is about 872.6092517057.

The spelling of 664445615 in words is "six hundred sixty-four million, four hundred forty-five thousand, six hundred fifteen".