638902144 has 16 divisors (see below), whose sum is σ = 1272813120. Its totient is φ = 319451008.

The previous prime is 638902141. The next prime is 638902153. The reversal of 638902144 is 441209836.

It is a tau number, because it is divible by the number of its divisors (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638902141) 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 as a sum of consecutive naturals, namely, 2495584 + ... + 2495839.

It is an arithmetic number, because the mean of its divisors is an integer number (79550820).

Almost surely, 2^638902144 is an apocalyptic number.

638902144 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

638902144 is a deficient number, since it is larger than the sum of its proper divisors (633910976).

638902144 is an equidigital number, since it uses as much as digits as its factorization.

638902144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4991437 (or 4991425 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 37.

The square root of 638902144 is about 25276.5136836550. The cubic root of 638902144 is about 861.2808316801.

The spelling of 638902144 in words is "six hundred thirty-eight million, nine hundred two thousand, one hundred forty-four".