638794816 has 56 divisors (see below), whose sum is σ = 1394460000. Its totient is φ = 290322560.

The previous prime is 638794811. The next prime is 638794837. The reversal of 638794816 is 618497836.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (638794811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 81435 + ... + 88933.

Almost surely, 2^638794816 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638794816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (697230000).

638794816 is an abundant number, since it is smaller than the sum of its proper divisors (755665184).

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

638794816 is an equidigital number, since it uses as much as digits as its factorization.

638794816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7544 (or 7512 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 52.

The square root of 638794816 is about 25274.3905168849. The cubic root of 638794816 is about 861.2326006499.

The spelling of 638794816 in words is "six hundred thirty-eight million, seven hundred ninety-four thousand, eight hundred sixteen".