638755289 has 4 divisors (see below), whose sum is σ = 638933520. Its totient is φ = 638577060.

The previous prime is 638755261. The next prime is 638755291. The reversal of 638755289 is 982557836.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638755289 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 638755289.

It is not an unprimeable number, because it can be changed into a prime (638755219) 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 3 ways as a sum of consecutive naturals, for example, 83627 + ... + 90944.

It is an arithmetic number, because the mean of its divisors is an integer number (159733380).

Almost surely, 2^638755289 is an apocalyptic number.

It is an amenable number.

638755289 is a deficient number, since it is larger than the sum of its proper divisors (178231).

638755289 is a wasteful number, since it uses less digits than its factorization.

638755289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178230.

The product of its digits is 3628800, while the sum is 53.

The square root of 638755289 is about 25273.6085472574. The cubic root of 638755289 is about 861.2148366552.

The spelling of 638755289 in words is "six hundred thirty-eight million, seven hundred fifty-five thousand, two hundred eighty-nine".