638823845 has 16 divisors (see below), whose sum is σ = 842304960. Its totient is φ = 461251200.

The previous prime is 638823799. The next prime is 638823847. The reversal of 638823845 is 548328836.

It is a happy number.

638823845 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 638823845 - 2¹² = 638819749 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 638823845.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638823847) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34136 + ... + 49425.

It is an arithmetic number, because the mean of its divisors is an integer number (52644060).

Almost surely, 2^638823845 is an apocalyptic number.

It is an amenable number.

638823845 is a deficient number, since it is larger than the sum of its proper divisors (203481115).

638823845 is a wasteful number, since it uses less digits than its factorization.

638823845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83716.

The product of its digits is 1105920, while the sum is 47.

The square root of 638823845 is about 25274.9647873147. The cubic root of 638823845 is about 861.2456462278.

The spelling of 638823845 in words is "six hundred thirty-eight million, eight hundred twenty-three thousand, eight hundred forty-five".