638842317 has 4 divisors (see below), whose sum is σ = 851789760. Its totient is φ = 425894876.

The previous prime is 638842289. The next prime is 638842331. The reversal of 638842317 is 713248836.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 638842317 - 2¹⁴ = 638825933 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638842367) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 106473717 + ... + 106473722.

It is an arithmetic number, because the mean of its divisors is an integer number (212947440).

Almost surely, 2^638842317 is an apocalyptic number.

It is an amenable number.

638842317 is a deficient number, since it is larger than the sum of its proper divisors (212947443).

638842317 is a wasteful number, since it uses less digits than its factorization.

638842317 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 212947442.

The product of its digits is 193536, while the sum is 42.

The square root of 638842317 is about 25275.3302055581. The cubic root of 638842317 is about 861.2539473039.

The spelling of 638842317 in words is "six hundred thirty-eight million, eight hundred forty-two thousand, three hundred seventeen".