138897439 has 4 divisors (see below), whose sum is σ = 142127656. Its totient is φ = 135667224.

The previous prime is 138897433. The next prime is 138897503. The reversal of 138897439 is 934798831.

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 138897439 - 2²⁷ = 4679711 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 (138897433) 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, 1615044 + ... + 1615129.

It is an arithmetic number, because the mean of its divisors is an integer number (35531914).

Almost surely, 2^138897439 is an apocalyptic number.

138897439 is a deficient number, since it is larger than the sum of its proper divisors (3230217).

138897439 is an equidigital number, since it uses as much as digits as its factorization.

138897439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3230216.

The product of its digits is 1306368, while the sum is 52.

The square root of 138897439 is about 11785.4757646860. The cubic root of 138897439 is about 517.8827109809.

The spelling of 138897439 in words is "one hundred thirty-eight million, eight hundred ninety-seven thousand, four hundred thirty-nine".