138839881 has 4 divisors (see below), whose sum is σ = 139380372. Its totient is φ = 138299392.

The previous prime is 138839797. The next prime is 138839933. The reversal of 138839881 is 188938831.

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 86769225 + 52070656 = 9315^2 + 7216^2 .

It is a cyclic number.

It is not a de Polignac number, because 138839881 - 2⁹ = 138839369 is a prime.

It is a super-2 number, since 2×138839881² = 38553025112188322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138839581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 269860 + ... + 270373.

It is an arithmetic number, because the mean of its divisors is an integer number (34845093).

Almost surely, 2^138839881 is an apocalyptic number.

It is an amenable number.

138839881 is a deficient number, since it is larger than the sum of its proper divisors (540491).

138839881 is an equidigital number, since it uses as much as digits as its factorization.

138839881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 540490.

The product of its digits is 331776, while the sum is 49.

The square root of 138839881 is about 11783.0336076920. The cubic root of 138839881 is about 517.8111655977.

The spelling of 138839881 in words is "one hundred thirty-eight million, eight hundred thirty-nine thousand, eight hundred eighty-one".