138328791 has 4 divisors (see below), whose sum is σ = 184438392. Its totient is φ = 92219192.

The previous prime is 138328787. The next prime is 138328819. The reversal of 138328791 is 197823831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 197823831 = 3 ⋅65941277.

It is a cyclic number.

It is not a de Polignac number, because 138328791 - 2² = 138328787 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138328741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23054796 + ... + 23054801.

It is an arithmetic number, because the mean of its divisors is an integer number (46109598).

Almost surely, 2^138328791 is an apocalyptic number.

138328791 is a deficient number, since it is larger than the sum of its proper divisors (46109601).

138328791 is an equidigital number, since it uses as much as digits as its factorization.

138328791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46109600.

The product of its digits is 72576, while the sum is 42.

The square root of 138328791 is about 11761.3260731943. The cubic root of 138328791 is about 517.1750046987.

The spelling of 138328791 in words is "one hundred thirty-eight million, three hundred twenty-eight thousand, seven hundred ninety-one".