664571052536665 has 16 divisors (see below), whose sum is σ = 797969192556816. Its totient is φ = 531334252800000.

The previous prime is 664571052536647. The next prime is 664571052536669. The reversal of 664571052536665 is 566635250175466.

It can be written as a sum of positive squares in 8 ways, for example, as 95132244787776 + 569438807748889 = 9753576^2 + 23862917^2 .

It is a de Polignac number, because none of the positive numbers 2^k-664571052536665 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 664571052536665.

It is not an unprimeable number, because it can be changed into a prime (664571052536669) 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, 173714289 + ... + 177498721.

It is an arithmetic number, because the mean of its divisors is an integer number (49873074534801).

Almost surely, 2^{664571052536665} is an apocalyptic number.

It is an amenable number.

664571052536665 is a deficient number, since it is larger than the sum of its proper divisors (133398140020151).

664571052536665 is a wasteful number, since it uses less digits than its factorization.

664571052536665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3805740.

The product of its (nonzero) digits is 816480000, while the sum is 67.

The spelling of 664571052536665 in words is "six hundred sixty-four trillion, five hundred seventy-one billion, fifty-two million, five hundred thirty-six thousand, six hundred sixty-five".