638353647409 has 2 divisors, whose sum is σ = 638353647410. Its totient is φ = 638353647408.

The previous prime is 638353647313. The next prime is 638353647413. The reversal of 638353647409 is 904746353836.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 612423630625 + 25930016784 = 782575^2 + 161028^2 .

It is a cyclic number.

It is not a de Polignac number, because 638353647409 - 2²⁹ = 637816776497 is a prime.

It is not a weakly prime, because it can be changed into another prime (638353647439) 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, 319176823704 + 319176823705.

It is an arithmetic number, because the mean of its divisors is an integer number (319176823705).

Almost surely, 2^638353647409 is an apocalyptic number.

It is an amenable number.

638353647409 is a deficient number, since it is larger than the sum of its proper divisors (1).

638353647409 is an equidigital number, since it uses as much as digits as its factorization.

638353647409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 39191040, while the sum is 58.

The spelling of 638353647409 in words is "six hundred thirty-eight billion, three hundred fifty-three million, six hundred forty-seven thousand, four hundred nine".