664560713321 has 2 divisors, whose sum is σ = 664560713322. Its totient is φ = 664560713320.

The previous prime is 664560713317. The next prime is 664560713329. The reversal of 664560713321 is 123317065466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 664125573721 + 435139600 = 814939^2 + 20860^2 .

It is a cyclic number.

It is not a de Polignac number, because 664560713321 - 2² = 664560713317 is a prime.

It is not a weakly prime, because it can be changed into another prime (664560713329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332280356660 + 332280356661.

It is an arithmetic number, because the mean of its divisors is an integer number (332280356661).

Almost surely, 2^664560713321 is an apocalyptic number.

It is an amenable number.

664560713321 is a deficient number, since it is larger than the sum of its proper divisors (1).

664560713321 is an equidigital number, since it uses as much as digits as its factorization.

664560713321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 544320, while the sum is 44.

Adding to 664560713321 its reverse (123317065466), we get a palindrome (787877778787).

The spelling of 664560713321 in words is "six hundred sixty-four billion, five hundred sixty million, seven hundred thirteen thousand, three hundred twenty-one".