638793820 has 24 divisors (see below), whose sum is σ = 1533105504. Its totient is φ = 219014976.

The previous prime is 638793811. The next prime is 638793829. The reversal of 638793820 is 28397836.

It is an interprime number because it is at equal distance from previous prime (638793811) and next prime (638793829).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638793829) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 2281267 + ... + 2281546.

It is an arithmetic number, because the mean of its divisors is an integer number (63879396).

Almost surely, 2^638793820 is an apocalyptic number.

It is an amenable number.

638793820 is an abundant number, since it is smaller than the sum of its proper divisors (894311684).

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

638793820 is a wasteful number, since it uses less digits than its factorization.

638793820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4562829 (or 4562827 counting only the distinct ones).

The product of its (nonzero) digits is 435456, while the sum is 46.

The square root of 638793820 is about 25274.3708131380. The cubic root of 638793820 is about 861.2321530424.

The spelling of 638793820 in words is "six hundred thirty-eight million, seven hundred ninety-three thousand, eight hundred twenty".