638138323 has 2 divisors, whose sum is σ = 638138324. Its totient is φ = 638138322.

The previous prime is 638138321. The next prime is 638138327. The reversal of 638138323 is 323831836.

638138323 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 638138323 - 2¹ = 638138321 is a prime.

Together with 638138321, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (638138321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319069161 + 319069162.

It is an arithmetic number, because the mean of its divisors is an integer number (319069162).

Almost surely, 2^638138323 is an apocalyptic number.

638138323 is a deficient number, since it is larger than the sum of its proper divisors (1).

638138323 is an equidigital number, since it uses as much as digits as its factorization.

638138323 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 62208, while the sum is 37.

The square root of 638138323 is about 25261.3998622404. The cubic root of 638138323 is about 860.9374683393.

The spelling of 638138323 in words is "six hundred thirty-eight million, one hundred thirty-eight thousand, three hundred twenty-three".