638030642 has 18 divisors (see below), whose sum is σ = 978347223. Its totient is φ = 312067392.

The previous prime is 638030633. The next prime is 638030663. The reversal of 638030642 is 246030836.

It can be written as a sum of positive squares in 5 ways, for example, as 312264241 + 325766401 = 17671^2 + 18049^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=17861.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 638030599 and 638030608.

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 8 ways as a sum of consecutive naturals, for example, 1893098 + ... + 1893434.

Almost surely, 2^638030642 is an apocalyptic number.

638030642 is a deficient number, since it is larger than the sum of its proper divisors (340316581).

638030642 is an frugal number, since it uses more digits than its factorization.

638030642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 782 (or 392 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 32.

The square root of 638030642 is about 25259.2684375459. The cubic root of 638030642 is about 860.8890400601.

Multiplying 638030642 by its sum of digits (32), we get a square (20416980544 = 142888²).

The spelling of 638030642 in words is "six hundred thirty-eight million, thirty thousand, six hundred forty-two".