138238913 has 4 divisors (see below), whose sum is σ = 138330048. Its totient is φ = 138147780.

The previous prime is 138238897. The next prime is 138238943. The reversal of 138238913 is 319832831.

138238913 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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: 319832831 = 577 ⋅554303.

It is a cyclic number.

It is not a de Polignac number, because 138238913 - 2⁴ = 138238897 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (138238943) 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, 43253 + ... + 46338.

It is an arithmetic number, because the mean of its divisors is an integer number (34582512).

Almost surely, 2^138238913 is an apocalyptic number.

It is an amenable number.

138238913 is a deficient number, since it is larger than the sum of its proper divisors (91135).

138238913 is an equidigital number, since it uses as much as digits as its factorization.

138238913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91134.

The product of its digits is 31104, while the sum is 38.

The square root of 138238913 is about 11757.5045396547. The cubic root of 138238913 is about 517.0629703550.

The spelling of 138238913 in words is "one hundred thirty-eight million, two hundred thirty-eight thousand, nine hundred thirteen".