138388939 has 4 divisors (see below), whose sum is σ = 149034256. Its totient is φ = 127743624.

The previous prime is 138388937. The next prime is 138388963. The reversal of 138388939 is 939883831.

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

It is a cyclic number.

It is not a de Polignac number, because 138388939 - 2¹ = 138388937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138388937) 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, 5322639 + ... + 5322664.

It is an arithmetic number, because the mean of its divisors is an integer number (37258564).

Almost surely, 2^138388939 is an apocalyptic number.

138388939 is a deficient number, since it is larger than the sum of its proper divisors (10645317).

138388939 is a wasteful number, since it uses less digits than its factorization.

138388939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10645316.

The product of its digits is 1119744, while the sum is 52.

The square root of 138388939 is about 11763.8828198856. The cubic root of 138388939 is about 517.2499530263.

The spelling of 138388939 in words is "one hundred thirty-eight million, three hundred eighty-eight thousand, nine hundred thirty-nine".