138921873 has 4 divisors (see below), whose sum is σ = 185229168. Its totient is φ = 92614580.

The previous prime is 138921859. The next prime is 138921883. The reversal of 138921873 is 378129831.

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.

It is a cyclic number.

It is not a de Polignac number, because 138921873 - 2⁹ = 138921361 is a prime.

It is not an unprimeable number, because it can be changed into a prime (138921833) 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, 23153643 + ... + 23153648.

It is an arithmetic number, because the mean of its divisors is an integer number (46307292).

Almost surely, 2^138921873 is an apocalyptic number.

It is an amenable number.

138921873 is a deficient number, since it is larger than the sum of its proper divisors (46307295).

138921873 is an equidigital number, since it uses as much as digits as its factorization.

138921873 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46307294.

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

The square root of 138921873 is about 11786.5123340198. The cubic root of 138921873 is about 517.9130768017.

The spelling of 138921873 in words is "one hundred thirty-eight million, nine hundred twenty-one thousand, eight hundred seventy-three".