664843615645 has 16 divisors (see below), whose sum is σ = 878474766528. Its totient is φ = 479003722240.

The previous prime is 664843615637. The next prime is 664843615649. The reversal of 664843615645 is 546516348466.

It is not a de Polignac number, because 664843615645 - 2³ = 664843615637 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 664843615645.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664843615649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 56480404 + ... + 56492173.

It is an arithmetic number, because the mean of its divisors is an integer number (54904672908).

Almost surely, 2^664843615645 is an apocalyptic number.

It is an amenable number.

664843615645 is a deficient number, since it is larger than the sum of its proper divisors (213631150883).

664843615645 is a wasteful number, since it uses less digits than its factorization.

664843615645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112972700.

The product of its digits is 49766400, while the sum is 58.

The spelling of 664843615645 in words is "six hundred sixty-four billion, eight hundred forty-three million, six hundred fifteen thousand, six hundred forty-five".