638817842 has 32 divisors (see below), whose sum is σ = 1043159040. Its totient is φ = 291654720.

The previous prime is 638817833. The next prime is 638817863. The reversal of 638817842 is 248718836.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1385492 + ... + 1385952.

It is an arithmetic number, because the mean of its divisors is an integer number (32598720).

Almost surely, 2^638817842 is an apocalyptic number.

638817842 is a deficient number, since it is larger than the sum of its proper divisors (404341198).

638817842 is a wasteful number, since it uses less digits than its factorization.

638817842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 938.

The product of its digits is 516096, while the sum is 47.

The square root of 638817842 is about 25274.8460331611. The cubic root of 638817842 is about 861.2429485233.

The spelling of 638817842 in words is "six hundred thirty-eight million, eight hundred seventeen thousand, eight hundred forty-two".