664821006709 has 2 divisors, whose sum is σ = 664821006710. Its totient is φ = 664821006708.

The previous prime is 664821006691. The next prime is 664821006791. The reversal of 664821006709 is 907600128466.

664821006709 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 659360240100 + 5460766609 = 812010^2 + 73897^2 .

It is a cyclic number.

It is not a de Polignac number, because 664821006709 - 2¹⁵ = 664820973941 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664821000709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332410503354 + 332410503355.

It is an arithmetic number, because the mean of its divisors is an integer number (332410503355).

Almost surely, 2^664821006709 is an apocalyptic number.

It is an amenable number.

664821006709 is a deficient number, since it is larger than the sum of its proper divisors (1).

664821006709 is an equidigital number, since it uses as much as digits as its factorization.

664821006709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 870912, while the sum is 49.

The spelling of 664821006709 in words is "six hundred sixty-four billion, eight hundred twenty-one million, six thousand, seven hundred nine".