638396478259 has 2 divisors, whose sum is σ = 638396478260. Its totient is φ = 638396478258.

The previous prime is 638396478197. The next prime is 638396478337. The reversal of 638396478259 is 952874693836.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 638396478259 - 2²⁵ = 638362923827 is a prime.

It is not a weakly prime, because it can be changed into another prime (638396478359) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319198239129 + 319198239130.

It is an arithmetic number, because the mean of its divisors is an integer number (319198239130).

Almost surely, 2^638396478259 is an apocalyptic number.

638396478259 is a deficient number, since it is larger than the sum of its proper divisors (1).

638396478259 is an equidigital number, since it uses as much as digits as its factorization.

638396478259 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 470292480, while the sum is 70.

The spelling of 638396478259 in words is "six hundred thirty-eight billion, three hundred ninety-six million, four hundred seventy-eight thousand, two hundred fifty-nine".