664571052536645 has 4 divisors (see below), whose sum is σ = 797485263043980. Its totient is φ = 531656842029312.

The previous prime is 664571052536639. The next prime is 664571052536647. The reversal of 664571052536645 is 546635250175466.

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

It can be written as a sum of positive squares in 2 ways, for example, as 76705349069281 + 587865703467364 = 8758159^2 + 24245942^2 .

It is a cyclic number.

It is not a de Polignac number, because 664571052536645 - 2⁸ = 664571052536389 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664571052536647) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66457105253660 + ... + 66457105253669.

It is an arithmetic number, because the mean of its divisors is an integer number (199371315760995).

Almost surely, 2^{664571052536645} is an apocalyptic number.

It is an amenable number.

664571052536645 is a deficient number, since it is larger than the sum of its proper divisors (132914210507335).

664571052536645 is a wasteful number, since it uses less digits than its factorization.

664571052536645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132914210507334.

The product of its (nonzero) digits is 544320000, while the sum is 65.

The spelling of 664571052536645 in words is "six hundred sixty-four trillion, five hundred seventy-one billion, fifty-two million, five hundred thirty-six thousand, six hundred forty-five".