638197944847 has 4 divisors (see below), whose sum is σ = 643069685016. Its totient is φ = 633326204680.

The previous prime is 638197944841. The next prime is 638197944869. The reversal of 638197944847 is 748449791836.

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

It is a cyclic number.

It is not a de Polignac number, because 638197944847 - 2⁷ = 638197944719 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638197944841) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2435869888 + ... + 2435870149.

It is an arithmetic number, because the mean of its divisors is an integer number (160767421254).

Almost surely, 2^638197944847 is an apocalyptic number.

638197944847 is a deficient number, since it is larger than the sum of its proper divisors (4871740169).

638197944847 is a wasteful number, since it uses less digits than its factorization.

638197944847 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4871740168.

The product of its digits is 292626432, while the sum is 70.

The spelling of 638197944847 in words is "six hundred thirty-eight billion, one hundred ninety-seven million, nine hundred forty-four thousand, eight hundred forty-seven".