138540191 has 16 divisors (see below), whose sum is σ = 155167200. Its totient is φ = 122923008.

The previous prime is 138540187. The next prime is 138540223. The reversal of 138540191 is 191045831.

138540191 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 138540191 - 2² = 138540187 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138542191) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 73031 + ... + 74903.

It is an arithmetic number, because the mean of its divisors is an integer number (9697950).

Almost surely, 2^138540191 is an apocalyptic number.

138540191 is a deficient number, since it is larger than the sum of its proper divisors (16627009).

138540191 is a wasteful number, since it uses less digits than its factorization.

138540191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2138.

The product of its (nonzero) digits is 4320, while the sum is 32.

The square root of 138540191 is about 11770.3097240472. The cubic root of 138540191 is about 517.4383269561.

The spelling of 138540191 in words is "one hundred thirty-eight million, five hundred forty thousand, one hundred ninety-one".