138155191 has 4 divisors (see below), whose sum is σ = 138358152. Its totient is φ = 137952232.

The previous prime is 138155177. The next prime is 138155203. The reversal of 138155191 is 191551831.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 191551831 = 6907 ⋅27733.

It is a cyclic number.

It is not a de Polignac number, because 138155191 - 2¹⁷ = 138024119 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 (138155111) 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, 100456 + ... + 101821.

It is an arithmetic number, because the mean of its divisors is an integer number (34589538).

Almost surely, 2^138155191 is an apocalyptic number.

138155191 is a deficient number, since it is larger than the sum of its proper divisors (202961).

138155191 is an equidigital number, since it uses as much as digits as its factorization.

138155191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202960.

The product of its digits is 5400, while the sum is 34.

The square root of 138155191 is about 11753.9436360738. The cubic root of 138155191 is about 516.9585658686.

The spelling of 138155191 in words is "one hundred thirty-eight million, one hundred fifty-five thousand, one hundred ninety-one".