638485076809 has 2 divisors, whose sum is σ = 638485076810. Its totient is φ = 638485076808.

The previous prime is 638485076797. The next prime is 638485076833. The reversal of 638485076809 is 908670584836.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 571455866809 + 67029210000 = 755947^2 + 258900^2 .

It is a cyclic number.

It is not a de Polignac number, because 638485076809 - 2⁹ = 638485076297 is a prime.

It is not a weakly prime, because it can be changed into another prime (638485076869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319242538404 + 319242538405.

It is an arithmetic number, because the mean of its divisors is an integer number (319242538405).

Almost surely, 2^638485076809 is an apocalyptic number.

It is an amenable number.

638485076809 is a deficient number, since it is larger than the sum of its proper divisors (1).

638485076809 is an equidigital number, since it uses as much as digits as its factorization.

638485076809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 69672960, while the sum is 64.

The spelling of 638485076809 in words is "six hundred thirty-eight billion, four hundred eighty-five million, seventy-six thousand, eight hundred nine".