638770889 has 4 divisors (see below), whose sum is σ = 645948180. Its totient is φ = 631593600.

The previous prime is 638770879. The next prime is 638770919. The reversal of 638770889 is 988077836.

638770889 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 368332864 + 270438025 = 19192^2 + 16445^2 .

It is a cyclic number.

It is not a de Polignac number, because 638770889 - 2²⁰ = 637722313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638770859) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3588512 + ... + 3588689.

It is an arithmetic number, because the mean of its divisors is an integer number (161487045).

Almost surely, 2^638770889 is an apocalyptic number.

It is an amenable number.

638770889 is a deficient number, since it is larger than the sum of its proper divisors (7177291).

638770889 is an equidigital number, since it uses as much as digits as its factorization.

638770889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7177290.

The product of its (nonzero) digits is 4064256, while the sum is 56.

The square root of 638770889 is about 25273.9171677047. The cubic root of 638770889 is about 861.2218476041.

The spelling of 638770889 in words is "six hundred thirty-eight million, seven hundred seventy thousand, eight hundred eighty-nine".