638353647329 has 4 divisors (see below), whose sum is σ = 638444678676. Its totient is φ = 638262615984.

The previous prime is 638353647313. The next prime is 638353647409. The reversal of 638353647329 is 923746353836.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 304527385600 + 333826261729 = 551840^2 + 577777^2 .

It is a cyclic number.

It is not a de Polignac number, because 638353647329 - 2⁴ = 638353647313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638353047329) 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 in 3 ways as a sum of consecutive naturals, for example, 45505154 + ... + 45519179.

It is an arithmetic number, because the mean of its divisors is an integer number (159611169669).

Almost surely, 2^638353647329 is an apocalyptic number.

It is an amenable number.

638353647329 is a deficient number, since it is larger than the sum of its proper divisors (91031347).

638353647329 is an equidigital number, since it uses as much as digits as its factorization.

638353647329 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91031346.

The product of its digits is 58786560, while the sum is 59.

The spelling of 638353647329 in words is "six hundred thirty-eight billion, three hundred fifty-three million, six hundred forty-seven thousand, three hundred twenty-nine".