638843420 has 24 divisors (see below), whose sum is σ = 1348389504. Its totient is φ = 254238656.

The previous prime is 638843417. The next prime is 638843431. The reversal of 638843420 is 24348836.

638843420 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 77132 + ... + 85011.

It is an arithmetic number, because the mean of its divisors is an integer number (56182896).

Almost surely, 2^638843420 is an apocalyptic number.

It is an amenable number.

638843420 is an abundant number, since it is smaller than the sum of its proper divisors (709546084).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

638843420 is a wasteful number, since it uses less digits than its factorization.

638843420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 162349 (or 162347 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 38.

The square root of 638843420 is about 25275.3520252439. The cubic root of 638843420 is about 861.2544429727.

The spelling of 638843420 in words is "six hundred thirty-eight million, eight hundred forty-three thousand, four hundred twenty".