138473891 has 8 divisors (see below), whose sum is σ = 149739840. Its totient is φ = 127554688.

The previous prime is 138473873. The next prime is 138473893. The reversal of 138473891 is 198374831.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138473891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138473893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 85856 + ... + 87453.

It is an arithmetic number, because the mean of its divisors is an integer number (18717480).

Almost surely, 2^138473891 is an apocalyptic number.

138473891 is a deficient number, since it is larger than the sum of its proper divisors (11265949).

138473891 is a wasteful number, since it uses less digits than its factorization.

138473891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173373.

The product of its digits is 145152, while the sum is 44.

The square root of 138473891 is about 11767.4929785405. The cubic root of 138473891 is about 517.3557717669.

The spelling of 138473891 in words is "one hundred thirty-eight million, four hundred seventy-three thousand, eight hundred ninety-one".