138888889 has 4 divisors (see below), whose sum is σ = 140187024. Its totient is φ = 137590756.

The previous prime is 138888857. The next prime is 138888907. The reversal of 138888889 is 988888831.

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, and also an emirpimes, since its reverse is a distinct semiprime: 988888831 = 7 ⋅141269833.

It is a cyclic number.

It is not a de Polignac number, because 138888889 - 2⁵ = 138888857 is a prime.

It is a Duffinian number.

It is a plaindrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (138888829) 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, 648907 + ... + 649120.

It is an arithmetic number, because the mean of its divisors is an integer number (35046756).

Almost surely, 2^138888889 is an apocalyptic number.

It is an amenable number.

138888889 is a deficient number, since it is larger than the sum of its proper divisors (1298135).

138888889 is a wasteful number, since it uses less digits than its factorization.

138888889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1298134.

The product of its digits is 7077888, while the sum is 61.

The square root of 138888889 is about 11785.1130244898. The cubic root of 138888889 is about 517.8720844637.

The spelling of 138888889 in words is "one hundred thirty-eight million, eight hundred eighty-eight thousand, eight hundred eighty-nine".