138318923 has 4 divisors (see below), whose sum is σ = 140928768. Its totient is φ = 135709080.

The previous prime is 138318907. The next prime is 138318949. The reversal of 138318923 is 329813831.

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 138318923 - 2⁴ = 138318907 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138318823) 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, 1304843 + ... + 1304948.

It is an arithmetic number, because the mean of its divisors is an integer number (35232192).

Almost surely, 2^138318923 is an apocalyptic number.

138318923 is a deficient number, since it is larger than the sum of its proper divisors (2609845).

138318923 is an equidigital number, since it uses as much as digits as its factorization.

138318923 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2609844.

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

The square root of 138318923 is about 11760.9065551938. The cubic root of 138318923 is about 517.1627064531.

The spelling of 138318923 in words is "one hundred thirty-eight million, three hundred eighteen thousand, nine hundred twenty-three".