639188889 has 8 divisors (see below), whose sum is σ = 857896512. Its totient is φ = 423303600.

The previous prime is 639188887. The next prime is 639188917. The reversal of 639188889 is 988881936.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 639188889 - 2¹ = 639188887 is a prime.

It is not an unprimeable number, because it can be changed into a prime (639188887) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 705054 + ... + 705959.

It is an arithmetic number, because the mean of its divisors is an integer number (107237064).

Almost surely, 2^639188889 is an apocalyptic number.

It is an amenable number.

639188889 is a deficient number, since it is larger than the sum of its proper divisors (218707623).

639188889 is a wasteful number, since it uses less digits than its factorization.

639188889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1411167.

The product of its digits is 5971968, while the sum is 60.

The square root of 639188889 is about 25282.1852101435. The cubic root of 639188889 is about 861.4096625903.

The spelling of 639188889 in words is "six hundred thirty-nine million, one hundred eighty-eight thousand, eight hundred eighty-nine".