18438999389 has 4 divisors (see below), whose sum is σ = 18450264924. Its totient is φ = 18427733856.

The previous prime is 18438999373. The next prime is 18438999427. The reversal of 18438999389 is 98399983481.

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 227496889 + 18211502500 = 15083^2 + 134950^2 .

It is a cyclic number.

It is not a de Polignac number, because 18438999389 - 2⁴ = 18438999373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18438999349) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5630312 + ... + 5633585.

It is an arithmetic number, because the mean of its divisors is an integer number (4612566231).

Almost surely, 2^18438999389 is an apocalyptic number.

It is an amenable number.

18438999389 is a deficient number, since it is larger than the sum of its proper divisors (11265535).

18438999389 is a wasteful number, since it uses less digits than its factorization.

18438999389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11265534.

The product of its digits is 120932352, while the sum is 71.

The spelling of 18438999389 in words is "eighteen billion, four hundred thirty-eight million, nine hundred ninety-nine thousand, three hundred eighty-nine".