639664044073 has 2 divisors, whose sum is σ = 639664044074. Its totient is φ = 639664044072.

The previous prime is 639664044011. The next prime is 639664044127. The reversal of 639664044073 is 370440466936.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 628298778409 + 11365265664 = 792653^2 + 106608^2 .

It is a cyclic number.

It is not a de Polignac number, because 639664044073 - 2²⁹ = 639127173161 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 639664044073.

It is not a weakly prime, because it can be changed into another prime (639664041073) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319832022036 + 319832022037.

It is an arithmetic number, because the mean of its divisors is an integer number (319832022037).

Almost surely, 2^639664044073 is an apocalyptic number.

It is an amenable number.

639664044073 is a deficient number, since it is larger than the sum of its proper divisors (1).

639664044073 is an equidigital number, since it uses as much as digits as its factorization.

639664044073 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7838208, while the sum is 52.

The spelling of 639664044073 in words is "six hundred thirty-nine billion, six hundred sixty-four million, forty-four thousand, seventy-three".