638439741 has 24 divisors (see below), whose sum is σ = 954475704. Its totient is φ = 410941440.

The previous prime is 638439731. The next prime is 638439757. The reversal of 638439741 is 147934836.

638439741 is a `hidden beast` number, since 638 + 4 + 3 + 9 + 7 + 4 + 1 = 666.

638439741 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 49406841 + 589032900 = 7029^2 + 24270^2 .

It is not a de Polignac number, because 638439741 - 2⁹ = 638439229 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638439701) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 26875 + ... + 44711.

It is an arithmetic number, because the mean of its divisors is an integer number (39769821).

Almost surely, 2^638439741 is an apocalyptic number.

It is an amenable number.

638439741 is a deficient number, since it is larger than the sum of its proper divisors (316035963).

638439741 is a wasteful number, since it uses less digits than its factorization.

638439741 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17981 (or 17978 counting only the distinct ones).

The product of its digits is 435456, while the sum is 45.

The square root of 638439741 is about 25267.3651376632. The cubic root of 638439741 is about 861.0729986224.

The spelling of 638439741 in words is "six hundred thirty-eight million, four hundred thirty-nine thousand, seven hundred forty-one".